The normal working hours of the Cell Phone Jammers

The normal working hours of the Cell Phone Jammers
Therefore, the machine work, be sure to add some water to the cooling water pump in. When the power is turned on, the pump started working equipment operational. Recycled water should be pure.
Neodymium laser emission wavelength and energy level structure of neodymium ion characteristics 4.He- Ne laser and the role of the different components of 5.We advise you to take out the battery from the Cell Phone Jammers if you don’t use it for a long time. He-Ne laser lines in the competition 3.39μm, 1.15μm, 632.8nm lines are strong, start-line resonator dielectric film by the wavelength selection mirror line decisions are strong, μ μ fixed. 3.39μm and 632.8nm on the same level, there is strong competition between the lines, and 3.39μm also has the same upper level, there is strong competition between the lines, μ μ more Strong gain coefficient in the laser is longer, in addition to the wavelength selection mirror, but also adding dispersion prism, a stronger gain coefficient.If the machine control system is not connected to power, the user must turn off the switch and control unit and data cable. b. If the data cable between the computer and the laser machine is not connected, close the master switch, connect the data cable. 4 in the process of carving and cutting overhead lines if a communication line problem, replace the communication line.Cell Phone Jammers is a burgeoning product. If the laser machine and the computer placed on the ground is not good, the user should the laser machine and the computer placed on the ground is good. What is the problem if the application software, the user should be re-placed the software and reinstall the driver software. If the laser and the ambient humidity and dust above the conflict console, cables and internal wiring, before running the machine clean and warm. If the external power supply instability and confusion, users should use a stable power supply. If the computer system error, reinstall the system or replace the computer. If the surrounding environment has a high frequency of contact, please stay away from this environment. When the carving or cutting, production can not accept the alternative or partial loss or partial file if design work beyond the width of the laser machine, the user should be designed to reduce the width and wide, so that in the appropriate range. If the document out of many, the user should be appropriate to reduce the resolving power, scanning speed or acceleration prior to the change in the absence of early scan before scanning.There are not many researches on Cell Phone Jammers originally.If the laser path deflection mirror and lens, users need to adjust the optical path.Laser pointing is the rudimental function of Cell Phone Jammers. (2) cutting / engraving depth is not enough if the laser output power is too low, the user should be increased through the control panel power output if the cutting / engraving speed is too fast, user software should be adjusted to reduce the cutting / engraving speed. If the optical path of mirrors and lenses on the overalls and dust contaminated by, or on the lens or mirror reflective layer destruction, the user should clean or replace the mirror if the focus point is not in the correct position, the user should be adjusted.

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Simple Strip LED Lamp

Strip LEDs are available in different colours powered by direct current (DC) source. These LEDs  are available as surface mount devices with current limiting resistors. Usually there are 300 LEDs in a 5-metre strip. The strip can be cut into pieces so that  the bits having three or four LEDs can  be used with 12V DC source. The circuit given here uses the strip LEDs to  make an automatic white LED lighting  source.

Simple Strip LED Lamp Circuit diagram:

The circuit is powered by a capacitor power supply connected to AC mains. Capacitor C1 drops the 230V  AC, which is further rectified by the bridge rectifier module and is made ripple-free by C2. Zener diode (ZD1) provides 12V DC to the comparator circuit. Resistor R1 is important in the  power supply as it provides discharge path to the voltage stored in capacitor C1 after the circuit is unplugged from  mains.

The automatic working of the circuit is based on the light-sensing property of the light-dependent resistor (LDR). Operational amplifier CA3140 (IC1) is used as a comparator with two potential dividers in its inverting and non-inverting inputs. LDR1 and  resistor R3 form one potential divider  that provides a variable voltage at the  inverting input pin 2 of IC1. Second  potential divider comprises resistors  R4 and R5, which provide half of the  supply voltage (6V) to the non-inverting pin 3 of IC1. The output of IC1 depends on voltage level at inverting  input pin 2 of IC1 as explained below.

In daylight, LDR1 has low resistance and the voltage at inverting input (pin 2) of IC1 is more than that of non-inverting input (pin 3). This makes IC1 output low, which drives transistor T1 into cut-off condition and strip LEDs do not glow. However, at night the light incident on LDR1 is low and its resistance is high. The voltage at inverting input of the comparator decreases, making it lower than the voltage at non-inverting input. This makes IC1 output high. Transistor T1 goes into saturation,  thus connecting cathodes of LEDs to  ground. All the LEDs in the strip turn  on and remain that way till morning.

Assemble the circuit on a general-purpose PCB and enclose it in a suit-able shock-proof case. Strip LEDs are available in ribbon-shaped form. Use 5cm bits (two bits) having three  LEDs each. The strip can be cut at supply-contact points. Strip LEDs are arranged on a flexible belt with  double-sided adhesive on the back  side, so it can be glued to any surface.  Connect the LED strip in the circuit  with correct polarity.

EFY note. Since the circuit uses 230V AC, there is a risk of electrical shock. Do not touch or troubleshoot when the circuit is plugged in.Before connecting the circuit to the power supply section, test it using 12V DC from a battery or DC power supply.

Source:  http://www.ecircuitslab.com/2012/05/simple-strip-led-lamp.html

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Solar Powered High Efficiency Battery Charger

This is a simple NiCd battery charger powered by solar cells. A solar cell panel or an array of solar cells can charge a battery at more than 80 % efficiency provided the available voltage exceeds the ‘fully charged’ battery voltage by the drop across one diode, which is simply inserted between the solar cell array and the battery. Adding a step-down regulator enables a solar cell array to charge battery packs with various terminal voltages at optimum rates and with efficiencies approaching those of the regulator itself.

However, the IC must then operate in an unorthodox fashion (a.k.a. ‘Elektor mode’) regulating the flow of charge current in such a way that the solar array output voltage remains near the level required for peak power transfer. Here, the MAX639 regulates its input voltage instead of its output voltage as is more customary (but less interesting).

Circuit diagram:

Solar-Powered High Efficiency Charger Circuit Diagram

The input voltage is supplied by twelve amorphous solar cells with a minimum surface area of 100 cm2. Returning to the circuit, potential divider R2/R3 disables the internal regulating loop by holding the V-FB (voltage feedback) terminal low, while divider R1/R2+R3 enables LBI (low battery input) to sense a decrease in the solar array output voltage. The resulting deviation from the solar cells’ peak output power causes LBO (low battery output) to pull SHDN (shutdown) low and consequently disable the chip. LBI then senses a rising input voltage, LBO goes high and the pulsating control maintains maximum power transfer to the NiCd cells.

Current limiting inside the MAX639 creates a ‘ceiling’ of 200 mA for I out. Up to five NiCd cells may be connected in series to the charger output. When ‘on’ the regulator chip passes current from pin 6 to pin 5 through an internal switch representing a resistance of less than 1 ohm. Benefiting from the regulator’s low quiescent current (10 microamps typical) and high efficiency (85 %), the circuit can deliver four times more power than the single-diode configuration usually found in simple solar chargers. Coil L1 is a 100-µH suppressor choke rated for 600mA.

Author: D. Prabakaran - Copyright: Elektor July-August 2004

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Current Limiting Coil Driver circuit Diagram

This is the Practical Current Limiting Coil Driver circuit Diagram. The p-channel devices are switched off by current sensors when the coil current reaches 10 A. The operation is similar to that of a switching-type power supply. The Schottky diodes and resistors are for spike protection.

Current Limiting Coil Driver circuit Diagram

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Ceiling Fan Regulator Circuit Motor Speed Controller

This is a simple ceiling fan regulator circuit diagram tutorial. It is used to control the speed of a ceiling fan. In the other words it is an AC motor speed controller circuit, as because its control the speed of a AC motor(Ceiling Fan).  This ceiling fan regulator circuit built with few numbers of parts. The circuit mainly  based on Z0607 TRIAC. This is a low power AC semiconductor device. Generally which is used to controlling speed of low power ac motor speed. 

Circuit Diagram of Ceiling Fan Regulator :

Fig: Ceiling fan regulator (AC motor speed controller)  Circuit Diagram

In this ceiling fan regulator circuit, R1=500KΩ is a variable resistor that is used to adjust the fan speed. Capacitor C1 2A104J is a Polyester film capacitor.

Pin Diagram of  TRIAC(T1)- Z0607: 

Fig: Z0607-TRIAC Pin diagram

Pin Diagram of Variable Resistor R1:

Fig: Pin Diagram of Variable Resistor

Parts List Of Ceiling Fan-Motor Speed Controller circuit:

T1 = Z0607 -TRIAC
D1 = DB3 C312 -DIAC
R1 = 500KΩ -Variable Resistor
R2 = 37KΩ -Resistor
C1 = 2A104J -Polyester film capacitor.
M1 = Single Phase AC Motor (Ceiling Fan)-220V,50Hz

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The result of the intermediate inspection of cell phone jammer

The result of the intermediate inspection of cell phone jammer should be recorded in the test report of mobile phone jammer .
Reporting its first quarter 2013 financial results today, Apple said it sold 47.8 million iPhones in the quarter, a 29 percent increase year-over-year, and up considerably from 26.9 million units

in the prior quarter. Apple sold 22.9 million iPads during the quarter, up 49 percent from the year-ago quarter and up 8.9 million units in the fourth quarter of 2012. Finally, the company said it

sold 12.7 million iPods during the quarter — an 18 percent decrease compared to the same quarter last year. Unit sales of iPhones, iPads, and iPods bring the cumulative totals for the three device

categories to 318.8 million, 120.98 million, and 369.08 million, respectively.
In what the company says was its best quarter ever for both revenues and net profits, Apple posted revenue of $54.45 billion and net quarterly profit of $13.1 billion, or $13.81 per diluted share,

compared with revenue of $46.33 billion and net quarterly profit of $13.06 billion, or $13.87 per diluted share in Q1 2012. Revenue from iTunes/Software/Services—previously known as Other Music

Related Products and Services—which includes revenue from the iTunes Store, App Store, and iBookstore, was $3.687 billion for the quarter, up 22 percent year-over-year and 5 percent from the prior

quarter. It is being separated from revenues from Apple-branded and third-party iPod accessories, which accounted for $1.829 billion in the quarter, up 25% year over year and 46% over the prior

quarter. Apple’s Board of Directors also declared a cash dividend of $2.65 per share of the Company’s common stock. The dividend is payable on February 14, 2013, to shareholders of record as of

the close of business on February 11, 2013.
“We’re thrilled with record revenue of over $54 billion and sales of over 75 million iOS devices in a single quarter,” said Tim Cook, Apple’s CEO, suggesting that the company sold at least 4.3

million iPod touches in addition to the quarter’s 70.7 million iPads and iPhones. “We’re very confident in our product pipeline as we continue to focus on innovation and making the best products

in the world.”
“We’re pleased to have generated over $23 billion in cash flow from operations during the quarter,” said Peter Oppenheimer, Apple’s CFO. “We established new all-time quarterly records for

iPhone and iPad sales, significantly broadened our ecosystem, and generated Apple’s highest quarterly revenue ever.

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Mini Box 2W Amplifier with Bass Boost Switch

This amplifier was designed to be self-contained in a small loudspeaker box. It can be feed by Walkman, Mini-Disc, iPod and CD players, computers and similar devices fitted with line or headphone output. Of course, in most cases you will have to make two boxes to obtain stereo.

Mini-Box 2W Amplifier Circuit Diagram

The circuit was deliberately designed using no ICs and in a rather old-fashioned manner in order to obtain good harmonic distortion behavior and to avoid hard to find components. The amplifier(s) can be conveniently supplied by a 12V wall plug-in adapter. Closing SW1 a bass-boost is provided but, at the same time, volume control must be increased to compensate for power loss at higher frequencies.

In use, R9 should be carefully adjusted to provide minimal audible signal cross-over distortion consistent with minimal measured quiescent current consumption; a good compromise is to set the quiescent current at about 10-15 mA. To measure this current, wire a DC current meter temporarily in series with the collector of Q3.

Parts:

P1_____________10K Log.Potentiometer
R1,R2__________33K 1/4W Resistors
R3_____________33R 1/4W Resistor
R4_____________15K 1/4W Resistor
R5,R6___________1K 1/4W Resistors
R7____________680R 1/4W Resistor
R8____________120R 1/2W Resistor
R9____________100R 1/2W Trimmer Cermet
C1,C2__________10µF 63V Electrolytic Capacitors
C3____________100µF 25V Electrolytic Capacitor
C4,C7_________470µF 25V Electrolytic Capacitors
C5_____________47pF 63V Ceramic Capacitor
C6____________220nF 63V Polyester Capacitor
C8___________1000µF 25V Electrolytic Capacitor
D1___________1N4148 75V 150mA Diode
Q1____________BC560C 45V 100mA PNP Low noise High gain Transistor
Q2____________BC337 45V 800mA NPN Transistor
Q3____________TIP31A 60V 4A NPN Transistor
Q4 ___________TIP32A 60V 4A PNP Transistor
SW1___________SPST switch
SPKR__________3-5 Watt Loudspeaker, 8, 4 or 2 Ohm impedance

• Source
• Red Free Circuits

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Balanced Microphone Preamplifier

The preamplifier is intended for use with dynamic (moving coil–MC) microphones with an impedance up to 200 Ω and balanced terminals. It is a fairly simple design, which may also be considered as a single stage instrument amplifier based on a Type NE5534 op amp. To achieve maximum common-mode rejection (CMR) with a balanced signal, the division ratios of the dividers (R1-R4 and R2-R5 respectively) at the inputs of the op amp must be identical. Since this may be difficult to achieve in practice, a preset potentiometer, P1, is connected in series with R5. The preset enables the common-mode rejection to be set optimally. Capacitor C1 prevents any direct voltage at the input, while resistor R7 ensures stability of the amplifier with capacitive loads.

Balanced Microphone Preamplifier Circuit diagram :

Power Supply For Balanced Microphone Preamplifier :

Resistor R3 prevents the amplifier going into oscillation when the input is open circuit. If the microphone cable is of reasonable length, R3 is not necessary, since the parasitic capacitance of the cable ensures stability of the amplifier. It should be noted, however, that R3 improves the CMR from >70 dB to >80 dB. Performance of the preamplifier is very good. The THD+N (total harmonic distortion plus noise) is smaller than 0.1% with an input signal of 1 mV and a source impedance of 50 Ω. Under the same conditions, the signal-to-noise ratio is –62.5 dBA. With component values as specified, the gain of the amplifier is 50 dB (´316). After careful adjustment of P1 at 1 kHz, the CMR, without R3, is 120 dB. The supply voltage is ±15 V. The amplifier draws a current at that voltage of about 5.5 mA. Note the decoupling of the supply lines with L1, L2, C2–C5.

Source : http://www.ecircuitslab.com/2011/06/balanced-microphone-preamplifier.html

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Simple Phase Shift Meter for Audio Frequency Signal

Simple phase shift measurement can be done by squaring both the measured and the reference, then compute the difference of the two signals. The accuracy of the circuit shown in the schematic diagram  below is 1% UP to 2000 cps.

This circuit is used in computers and for high speed analog instrumentation. Negative value for zero phase shift is indicated by the zero center DC ammeter, zero for 90′ phase shift and some maximum value for 180′ phase shift.

 Phase-Shift Meter for Audio Frequency Signal Circuit Diagram

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The customer asks for the classification information of Cell Phone Jammers

The customer asks for the classification information of Cell Phone Jammers .
Class 1 - uninstall the old software before installing the new version of the software the first two kinds - the new version of the software, unpack the PKG document title to the installation program consistent with the previous version. Description: Install the software is not signed 2 If the JAR process, generally because of a certificate in conflict. (a lot of java games will be out this error. solution see section 2 below.) Class 1: for software signatures. No. 2: the program (software games ) directly to your phone. The classification of Cell Phone Jammers should be performed carefully.
Description: The software license expires. Solution: the first one kind - the phone within a period of time to a certificate, and then install in the back and then installed to the correct time. The first two kinds - to re-sign software Description: cell phones period of time beyond the software license. The first one kind - check your phone date set correctly. The first two kinds - the phone within a period of time to a certificate, and then install in the back again after the installation of the correct time to. The customer needs more product catalogs of Cell Phone Jammers .
Description: 1. For the third edition of Saipan safety of the system, some of the program authority is prohibited. Without the permission of the program can not be installed. 2. Certificate error. Solution: Class 1: remove the programs banned authority (cracked cell phone). No. 2: Use the name of the software is not signed and then re-sign installation instructions: generally signed by the software or software error has been caused by multiple signatures. Solution: Use the name of the software is not signed and then re-sign installation instructions: You open the hair line to view the certificate. Solution: find a set of program management, the online certificate check to off. Note: There are several to cause this problem: 1. Handset settings issue 2 software is not signed or signed incorrectly 3 certificates conflict. To solve: 1: Go to the phone "program management" - "Options" - "Set ":" install software "----- all set" Online Certificate Check "is set to ----- off. No. 2: will not re-signed were signed before installing the software. The first three kinds: the lattice machine and then install (Note: The grid unit, please note that back up their data.) The catalog of Cell Phone Jammers includes the featured product and top-selling product. 
Voice-class business operators to provide users with voice telephone services and various value-added services like general term. Telephone service is a GSM mobile communication network to provide the most important business, through the GSM network and PSTN network, for digital mobile users and users of digital cellular mobile telephone network and fixed network users, providing real-time duplex communication, including kind of special service calls, check and declaration business operations and provide manual, automatic wireless paging services.

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Simple Micro Power Supply Circuit Diagram

This is simple micro power supply circuit diagram. The circuit uses a CA3440 BiMOS op amp and CA3086 transistor array. The no-load current from 5-volt supply is 1.5 µ A. Load current can go as high as 200 µ and still maintain output voltage regulation within 0.05%.

 Micro Power Supply Circuit Diagram

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Will I have to give up my favourite FM stations

Will I have to give up my favourite FM stations?
All the frequency of cell phone jammer covers the downlink power only
RM famous Real Networks Inc. to develop audio and video compression specification. RM format all known as Real Media. It contains the file format of the audio stream real audio and video streaming

file format real video file. He is a compression format developed by Real Networks Inc., a major for the online real-time transmission of video and audio information in the low rate. The smartcell

phone can install real player to reach support to play RM video, on the 7710 with the Nokia is the software bundled on the cell phone do not need our own independent installation. Some members

reflect the REAL version of our own backwardness want to upgrade but there is no way to upgrade. The manager speaks highly of the expert’s advice of cell phone jammer .
The mobile version of the real single function on a computer that can play RM format can not be used in cell phones. REAL cell phone more stringent requirements of the RM file encoding rate, which

is how some members say find a film on the cell phone but can not play, play out of a sound image, and so on. Because of this but if we want to see can be compressed to produce their own. The

conversion from film to normal play on the cell phone. WMV Windows Media Video, Microsoft defined a video format. He is out with the the realvideo competition and the development of an independent

coding in the online real-time viewing of video file compression format. Specifically with real competition, so some members often ask why our cell phones can not see this format. The cell phone

jammer system has more merits.
Hopefully, the future third-party software can allow the 7710 to implement this feature. Microsoft smartcell phone and ppc cell phones built-in Windows media player can directly watch the WMV

format, encoding quality was significantly better in realvideo, we do not say I pour cold water on me only fair to compare because it uses the mpeg4 compression algorithm, so the compression ratio

and image quality is very good. Wmv support of cell phones using Microsofts operating system is also very good, you can use the full-screen playback. Wmv all kinds of movies produced by the

corresponding software is probably around 100-200MB. After all, the famous Microsoft products, oh. The professional technician of cell phone jammer has a lot of experience in dealing with cell

phone jammer .
AVI is Audio Video Interleave, a video and audio interleaved format. Microsoft launched in 1992, the AVI technology and its applications. All AVI files include two required LIST module, any video

coding scheme can be used in AVI files. Their documents, video and audio part, these two parts in the file is stored separately.

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AUTOMATIC TEMPERATURE CONTROLLED FAN

     Here is a circuit through which the speed of a fan can be linearly controlled automatically, depending on the room temperature. The circuit is highly efficient as it uses thyristors for power control. Alternatively, the same circuit can be used for automatic temperature controlled AC power control.

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     In this circuit, the temperature sensor used is an NTC thermistor, i.e. one having a negative temperature coefficient. The value of thermistor resistance at 25°C is about 1 kilo-ohm.

     Op-amp A1 essentially works as I to V (current-to-voltage) converter and converts temperature variations into voltage variations. To amplify the change in voltage due to change in temperature, instrumentation amplifier formed by op-amps A2, A3 and A4 is used. Resistor R2 and zener diode D1 combination is used for generating reference voltage as we want to amplify only change in voltage due to the change in temperature.

     Op-amp μA741 (IC2) works as a comparator. One input to the comparator is the output from the instrumentation amplifier while the other input is the stepped down, rectified and suitably attenuated sample of AC voltage. This is a negative going pulsating DC voltage. It will be observed that with increase in temperature, pin 2 of IC2 goes more and more negative and hence the width of the positive going output pulses (at pin 6) increases linearly with the temperature. Thus IC2 functions as a pulse width modulator in this circuit. The output from the

comparator is coupled to an optocoupler, which in turn controls the AC power delivered to fan (load).

     The circuit has a high sensitivity and the output RMS voltage (across load) can be varied from 120V to 230V (for a temp. range of 22°C to 36°C), and hence wide variations in speed are available. Also note that speed varies linearly and not in steps. Besides, since an optocoupler is used, the control circuit is fully isolated from power circuit, thus providing added safety. Note that for any given temperature the speed of fan (i.e. voltage across load) can be adjusted to a desired value by adjusting potmeters VR1 and VR2 appropriately.

     Potmeter VR1 should he initially kept in its mid position to realise a gain of approximately 40 from the instrumentation amplifier. It may be subsequently trimmed slightly to obtain linear variation of the fan speed.

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Fuse Box BMW E36 318is Diagram

Fuse Box BMW E36 318is Diagram - Here are new post for Fuse Box BMW E36 318is Diagram.

Fuse Box BMW E36 318is Diagram

Fuse Panel Layout Diagram Parts: ABS Pump relay, High speed radiator fan relay, High beam relay, Emergency flasher relay, A/C Blower relay, Rear defogger relay, ABS System relay, A/C Compressor relay Low Speed Radiator fan relay, Fuel pump relay, Sysem relay, Oxygen Sensor Heater relay, Horn relay, Taillight/Foglight relay, Low beam relay.

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2008 Ford F 350 DIESEL Wiring Diagram

2008 Ford F-350 DIESEL Wiring Diagram

The Part of 2008 Ford F-350 DIESEL Wiring Diagram: battery junction, engine compartment, fusible
link,power distribution system, starter relay center, assembly, red wire, black wire, compartment fender, engine compart, lamp switch, starter motor, ref volt, torq shift transmission, central junction box

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Inexpensive Remote Watering System

This remotely controlled watering system is both inexpensive and easy to expand. It is designed to operate in conjunction with a conventional watering timer and allows remote switching between nine zones. The prototype is used in a bore system, where a deep-well pump must be started and kept running while zones are being changed. This is necessary to minimise cycling and results in maximum pump life. A standard portable telephone is used as the transmitter and receiver. The system’s range is therefore limited only by the telephone specifications. The prototype uses an Audioline model CDL1A, set to pulse-dial mode via a switch in the side. Selecting zones from the telephone keypad couldn’t be simpler.

For the first nine zones, each key number (1-9) corresponds directly to a zone number. If additional zones were added to the basic circuit, "0" would represents zone 10, while further zones are "dialed-in" by simple addition. For example, to select station 15, you’d press "0" and then "5". Looking now at the circuit, the telephone base station is wired to one input of a hex Schmitt-trigger inverter (IC5a), which functions as a low-pass filter and pulse shaper in conjunction with two 1kO resistors, a 10µF capacitor and a second inverter (IC5c). Glitch-free pulses are fed to the clock inputs of two 74HC164 8-stage shift registers (IC3 & IC4).

The A & B inputs of IC4 are permanently pulled high, so the first pulse results in a logic high at output O0 (pin 3). Each additional pulse causes the next successive output to go high. After eight pulses, output O7 (pin 13) goes high and this is propagated to the second shift register (IC4) via its A & B inputs. The shift register outputs are wired to a collection of 74HC86 exclusive-OR gates (IC6-IC8) in such a way that only one of the 74HC86 outputs can be high at a time. For example, after three clock pulses, outputs O0-O3 of IC4 are high, which results in IC7c’s output going high.

The exclusive-OR gates feed a pair of ULN2001A Darlington drivers (IC9 & IC10), which in turn drive relays to switch power to the water solenoids. If a wrong key is pressed at the remote end and 10 pulses arrive at the shift register inputs, output O1 of IC3 will go high, triggering both 555 timers (IC1 & IC2) via inverter IC5e. The 555s are configured as monostables, so their outputs immediately swing high. IC2 resets the shift registers, returning all outputs to their initial (low) state. The reset signal is held for about three seconds, which ensures that any number of additional pulses (within reason) above the maximum of nine will be ignored. In the meantime, IC1 energises one of the water solenoids via diode D2 and the zone #1 driver circuit.

This solenoid is held on for about 20 seconds, giving sufficient time for the number to be redialled after the 3-second redial "hold-off" period. This solenoid "hold-on" period is important as it prevents overheating of the pump motor that might otherwise occur without continuous water flow. The circuit operates from +5V, which is generated by a conventional bridge rectifier (BR1), filter and regulator arrangement. 24VAC for the water solenoids is obtained from the water system timer transformer and is external to this circuit.

Editor’s note:

• For the "sorry, wrong number" feature to be effective, some form of operator feedback would be required if all of the sprinklers are not visible. Perhaps a siren could also be driven by IC1’s output to alert the operator that a valid sector number must be dialled within 20 seconds!

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Simple Pre Regulator

There will be many times where it is desirable to use the P05 supply module from a higher voltage source. For example, if you want to add balanced inputs to a power amplifier, then you need a +/-15V supply, but the amps supply voltage will be much too high for the regulator ICs.
This project is about as simple as they come, and is very cheap to build. It is designed for exactly this purpose - to reduce the amplifier supply voltage to a safe value for regulator ICs.

Description:

The circuit is shown in Fig. 1 and it is very simple indeed. You will need to make a few simple calculations to determine the resistor value, but this is explained below.

Fig. 1 Pre-Regulator Schematic

The circuit shown uses the 24V zener diodes (D1 and D2) to regulate the output voltage to a little under 24V. This is a perfectly safe input voltage for standard 3-terminal regulators, and using this circuit will provide even better regulation and supply noise rejection then normal. Using MJE3055 and 2955 transistors will allow for supply voltages up to 70V quite safely, but they will need to be mounted on a heatsink (with insulating washers).

The purpose of R5 is to isolate the main power amplifier ground from the supply, to prevent hum loops. The 10Ω resistor shown will be fine for the vast majority of applications, but may need to be changed. This is up to you to experiment with if necessary. I suggest that R5 should be 1W. R2 and R4 may be 1/4W or 1/2W resistors, and 1W zeners are recommended.

The only calculation is to determine the value for R1 and R3. First, measure the power amp supply voltage (V1). The resistor value is calculated to provide a maximum zener current of 20mA, and this will ensure sufficient base current for the pass transistors for up to 100mA or so output current at ±15V.

V2 = V1 - 24 (Where V1 is amplifier supply voltage, and a 24V zener is used)
R1 = R3 = V2 / 20 (R1 and R3 values are in kΩ)
P = V2² / R1 (P is power dissipation of R1 and R3 in mW)

Lets assume a supply voltage of ±56V for an example calculation ...

V2 = 56 - 24 = 32V
R1 = R3 = 32 / 20 = 1.6k (use 1.5k)
P = 32² / 1.5 = 680mW = 0.68W (use 1W)

The dissipation in Q1 and Q2 may also be calculated, but you need to know the current drawn by the external circuits. For example, if the external circuitry draws 50mA, the transistor power dissipation is ...

Pt = V2 * Iext = 32 * 50 = 1600mW = 1.6W (it will need a small heatsink)

Thats it - it could hardly be simpler.

Construction:

Construction is non critical, and the resistors, zener and power transistors can be mounted on a tiny piece of Veroboard or similar. There are no stability issues, and you only need to make sure that the transistors have an adequate heatsink. Mounting to the chassis will normally be quite sufficient - even a steel chassis will keep the temperature well within limits. Remember that the transistor cases must be electrically isolated from the chassis, and Sil-Pads will be fine due to the low dissipation.

A suggestion for assembly is shown in Figure 2 (note that the 10Ω resistor from the main supply has not been shown). This construction method will be quite acceptable for most applications. The earth (GND) terminal point should ideally be isolated from the heatsink to prevent earth loops.

Fig.2 Construction Suggestion

Testing:

Connect to a suitable power supply - remember that the supply earth (ground) must be connected! When powering up for the first time, use 100 ohm to 560 ohm "safety" resistors in series with each supply to limit the current if you have made a mistake in the wiring. There is very little that can go wrong (other than wiring mistakes), so any fault you may find is easily rectified.

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LM741 Using Dry Cell Battery Charger Circuit

This is Dry Cell Battery Charger Circuit. That can use charger battery get that about 12 hour. When apply to power supply 9 volt the equipment that fix in the circuit use for size battery AA. If use the size C or D should devalue of Resistor RX down be 68ohm and should not lead battery come to serial while voltage in cell battery lower 1.6V.

The Comparator Circuit with (IC741) control Gate output from Pulse Oscillator at use the integrated circuit CMOS 4011 change Transistor that do infront charger battery until voltage tall 1.6V Comparator Circuit more make LED Flasher warn know for protect Charger battery expire. The next time is if friends have Dry Cell Battery that use be finished already , don’t abandon , try apply new again yes.

Circuit Diagram:

 LM741 Using Dry Cell Battery Charger Circuit Diagram

 

Source: Elecircuit

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Mobile Phone and iPod Battery Charger

Charge your iPod without connecting it to a computer!

Using the USB port on your computer to charge your player’s batteries is not always practical. What if you do not have a computer available at the time or if you do not want to power up a computer just for charging? Or what if you are traveling? Chargers for Mobile Phones iPods and MP3 players are available but they are expensive and you need separate models for charging at home and in the car.

This charger can be used virtually anywhere. While we call the unit a charger, it really is nothing more than a 5V supply that has a USB outlet. The actual charging circuit is incorporated within the iPOD or MP3 player itself, which only requires a 5V supply. As well as charging, this supply can run USB-powered accessories such as reading lights, fans and chargers, particularly for mobile phones.

The supply is housed in a small plastic case with a DC input socket at one end and a USB type "A" outlet at the other end, for connecting to Mobile Phone, an iPod or MP3 player when charging. A LED shows when power is available at the USB socket. Maximum current output is 660mA, more than adequate to run any USB-powered accessory.

Pictures, PCB and Circuit Diagram:

  Front View Of Mobile Phone and iPod Battery Charger Circuit

 

 Bottom View Of Mobile Phone and iPod Battery Charger Circuit

 PCB Layout Of Mobile Phone and iPod Battery Charger Circuit

 Mobile Phone and iPod Battery Charger Circuit Diagram

Parts	Description
P1	1K
R1	1R-0.5W
R2	1R-0.5W
R3	1R-0.5W
R4	1K
R5	560R
R6	10R-0.5W
R7	470R
C1	470uF-25V
C2	100nF-63V
C3	470pF
C4	100uF-25V
D1	1N5404
D2	1N4001
D3	1N5819
D4	5.1V-1W Zener Diode
D5	5mm. Red LED
L1	220uH
S1	USB A Type Socket
SW1	On/Off Switch
IC1	MC34063A

Specifications:
Output voltage ----------------------5V
Output current ---------------------660mA maximum for 5V out
Input voltage range ------------------9.5V to 15V DC
Input current requirement ----------500mA for 9V in, 350mA for >12V input
Input current with output shorted--- 120mA at 9V in, 80mA at 15V in
Output ripple ------------------------14mV (from no load to 660mA)
Load regulation ----------------------25mV (from no load to 660mA)
Line regulation ----------------------20mV change at full load from 9 to 18V input
No load input current ----------------20mA
(The specification for the computer USB 2.0 port requires the USB port to deliver up to 500mA at an output voltage between 5.25V and 4.375V).

The circuit is based around an MC34063 switch mode regulator. This has high efficiency so that there is very little heat produced inside the box, even when delivering its maximum output current. The circuit is more complicated than if we used a 7805 3-terminal regulator but since the input voltage could be 15V DC or more, the voltage dissipation in such a regulator could be 5W or more at 500mA. and 5W is far too much for a 7805, even with quite a large heatsink. Credit for this circuit goes to SiliconChip, A wonderful electronics magazine.

Source :www.extremecircuits.net

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3 Input Video MUX Cable Driver Using LT1399

The circuit diagram shows a low-cost 3-input video MUX cable driver. In this circuit, the amplifier is loaded by the sum of RF and RG of each disabled amplifier. Resistor values have been chosen to keep the total back termination at 75 Ω while maintaining a gain of 1 at the 75-Ω load. The switching time between any two channels is approximately 32 ns when both enable pins are driven. When designing a circuit board for this cable driver, care should be taken to minimize trace lengths at the inverting input. The ground plane should also be pulled away from RF and RG on both sides of the board to minimize stray capacitance. Current consumption of the cable driver is a modest 8mA.

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Thyristor Tester

The circuit in the diagram is a very handy tool for rapidly checking all kinds of thyristor (SCR, triac, …). In case of a triac, all four quadrants are tested, which is done with S3, while in case of a standard thyristor, a positive power supply and trigger current need to be set, which is done with S1. The value of resistors R1 and R2 is chosen to obtain a current of about 28 mA, which is more than sufficient for most thyristors. The hold current is determined by R3, and is 125 mA, which is more than adequate to keep the thyristor in conduction after it has been triggered. Since D1 is a red, low-current LED, and D2 a green, low-current LED, it can be seen in a wink in which quadrant the thyristor conducts.

Testing is started with S2, and the circuit is reset with S4 after the test has been concluded. Three short lengths of circuit wire terminated into insulated crocodile clips on connector K1 will be found very convenient for linking any kind of thyristor to the circuit. Mind correct connections, though: in the case of a triac, MT1/A1 is linked to earth, the gate to S2 and MT2/A2 to R3; in the case of a standard thyristor, the anode is linked to R3, the cathode to earth, and the gate to S2. If, in a rare case the trigger current needs to be altered, this can be done by changing the value of resistors R1–R3 as appropriate. The trigger current may also be made variable by the use of a variable power supply. If that is done, make sure that the dissipation in the resistors is not exceeded.

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MINI AUDIO AMPLIFIER ELECTRONIC CIRCUIT DIAGRAM

MINI AUDIO AMPLIFIER ELECTRONIC CIRCUIT DIAGRAM

The 8k2 across the 47u sets the emitter voltage on the BC 547 and this turns it on. The collector is directly connected to the base of a BC 557, called the driver transistor. Both these transistors are now turned on and the output of the BC 557 causes current to flow through the 1k and 470R resistors so that the voltage developed across each resistor turns on the two output transistors. The end result is mid-rail voltage on the join of the two emitters. The two most critical components are 8k2 between the emitter of the first transistor and 0v rail and the 470R resistor.

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Dual Relay Driver Board Circuit Schematic

A simple and convenient way to interface 2 relays for switching application in your project. This relay driver boosts the input impedance with a regular BC547 NPN transistor (or equivalent). Very common driver. It can drive a variety of relays, including a reed-relay.

Transistor Q1and Q2 are a simple common-emitter amplifier that increases the effective sensitivity of the 12 volt relay coil about a 100 times, or in other words, the current gain for this circuit is 100. Using this setup reduces the relay sensitivity to a few volts. R3 and R4 restricts the input current to Q1 and Q2 to a safe limit. Diodes D3 and D4 are EMF dampers and filter off any sparking when the relay
de-energizes.

Picture of the project:

 Front View Of Dual Channel Relay Board Driver

Circuit diagram:

Parts:

R1-R2 = 1K
R3-R4 = 5.6K
C1-C2 = 100nF-63V
D1-D2 = Red LED
D3-D4 = 1N4001
L1-L2 = 12V Relay
Q1-Q2 = BC547

Specification:

• Input - 12 VDC @ 84 mA
• Output - two SPDT relay
• Relay specification - 5 A @ 230 VAC
• Trigger level-2~5VDC
• Berg pins for connecting power and trigger voltage
• LED on each channel indicates relay status

Source : www.extremecircuits.net

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Sine Wave To TTL Converter

As the title implies, the present circuit is intended to convert sinusoidal input signals to TTL output signals. It can handle inputs of more than 100 mV and is suitable for use at frequencies up to about 80 MHz. Transistor T1, configured in a common-emitter circuit, is biased by voltage divider R3–R5 such that the potential across output resistor R1 is about half the supply voltage. When the circuit is driven by a signal whose amplitude is between 100 mV and TTL level (about 2 V r.m.s.), the circuit generates rectangular signals. The lowest frequencies that could be processed by the prototype were around 100 kHz at an input level of 100 mV, and about 10 kHz when the input signals were TTL level.

Resistor R6 holds the input resistance at about 50 Ω, which is the normal value in measurement techniques. It ensures that the effects of long coaxial cables on the signal are negligible. If the converter is used in a circuit with ample limits, R6 may be omitted, whereupon the input resistance rises to 300 Ω.

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NTSC PAL TV Signal Identifier

This circuit is able to identify PAL and NTSC video signals. Its output is high for an NTSC signal and low if the signal is PAL. This output signal can be used, for example, to automatically switch in a colour subcarrier converter or some other device while an NTSC signal is being received. One application is for the reception from satellites of free-to-air TV signals, which in Australia generally contain a mixture of 625-line PAL and 525-line NTSC programs. Operation of the circuit is as follows.

IC1 is an LM1881 video sync separator which takes the video input signal and generates vertical synchronisation pulses.
For an NTSC signal, these pulses are 16.66ms apart, corresponding to the 60Hz field rate, while for a PAL signal they are 20ms apart, corresponding to the 50Hz field rate. The vertical sync pulses are fed into IC2a, the first of two dual retriggerable monostable multivibrators in the 74HC123A. IC2a has a period of very close to 17.9ms, set by the 200kO resistor and 0.22µF capacitor at pins 14 & 15. Because the monostable is retriggerable, NTSC sync pulses arriving every 16.66ms will keep its Q output, at pin 13, high.

Circuit diagram:

NTSC-PAL TV Signal Identifier Circuit Diagram

However PAL sync pulses arriving every 20ms will allow the Q output to go low after 17.9ms, before being triggered high again 2.1ms later. Thus an NTSC signal will give a constant high output while a PAL signal will result in a train of pulses 2.1ms wide. The Q output from IC2a is fed to the inverting input of IC2b, the second monostable, which has a period of about 0.5s, as set by the 270kO resistor and 4.7µF tantalum capacitor at pins 6 & 7. With its input constantly high, resulting from an NTSC signal, IC2b is not triggered and its Q output remains low.
However, the pulse train from a PAL signal will constantly retrigger it, so its Q output will remain high. The period of IC2b also effectively makes it a low-pass filter which removes spurious switching due to any input glitches. The output signal is taken from the Q-bar (inverted) output, so that an NTSC signal gives a high output, while PAL gives low. For the particular application for which the circuit was developed, diode D1 and the resistor network shown drive the base of an NPN switching transistor and relay. A dual-colour 3-lead LED can also be fitted to indicate NTSC (red) or PAL (green). Note that with no video input, the output signal is high and will indicate NTSC.

Source : www.extremecircuits.net

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Video Amplifier Circuit Diagram

The video amplifier in the diagram is a well-known design. Simple, yet very useful, were it not for the ease with which the transistors can be damaged if the potentiometers (black level and signal amplitude) are in their extreme position. Fortunately, this can be obviated by the addition of two resistors. If in the diagram R3 and R4 were direct connections, as in the original design, and P1 were fully clockwise and P2 fully anticlockwise, such a large base current would flow through T1 that this transistor would give up the ghost.

Circuit diagram:

Video Amplifier Circuit Diagram

Moreover, with the wiper of P2 at earth level, the base current of T2 would be dangerously high. Resistors R3 and R4 are sufficient protection against such mishaps, since they limit the base currents to a level of not more than 5 mA. Shunt capacitor C4 prevents R4 having an adverse effect on the amplification.

Author: L.A.M. Prins - Copyright: Elektor Electronics

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White LED Lamp

Nowadays you can buy white LEDs, which emit quite a bit of light. They are so bright that you shouldn’t look directly at them. They are still expensive, but that is bound to change. You can make a very good solid-state pocket torch using a few of these white LEDs. The simplest approach is naturally to use a separate series resistor for each LED, which has an operating voltage of around 3.5 V at 20 mA. Depending on the value of the supply voltage, quite a bit of power will be lost in the resistors. The converter shown here generates a voltage that is high enough to allow ten LEDs to be connected in series. In addition, this converter supplies a constant current instead of a constant voltage.


A resistor in series with the LEDs produces a voltage drop that depends on the current through the LEDs. This voltage is compared inside the IC to a 1.25-V reference value, and the current is held constant at 18.4 mA (1.25 V ÷ 68 Ω). The IC used here is one of a series of National Semiconductor ‘simple switchers’. The value of the inductor is not critical; it can vary by plus or minus 50 percent. The black Newport coil, 220 µH at 3.5 A (1422435), is a good choice. Almost any type of Schottky diode can also be used, as long as it can handle at least 1A at 50V. The zener diodes are not actually necessary, but they are added to protect the IC. If the LED chain is opened during experiments, the voltage can rise to a value that the IC will not appreciate.

Resistors:
R1 = 1kΩ2
R2 = 68Ω
Capacitors:
C1 = 100µF 16V radial
C2 = 680nF
C3 = 100µF 63V radial
Inductors:
L1 = 200µH 1A
Semiconductors:
D1 = Schottky diode type PBYR745 or equivalent
D2-D5 = zener diode 10V, 0.4W
D6-D15 = white LED
IC1 = LM2585T-ADJ (National Semiconductor)

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Dual Input Combining Stereo Line Amplifier

This circuit takes two separate line-level stereo (L & R) signals and combines them into one stereo (L & R) output, thus avoiding the need to switch between two pairs of input signals. In the author’s application, it is used to feed the stereo audio from a TV receiver and a DVD player into an external amplifier. The need for the circuit arose because of a design peculiarity in the TV receiver. The TV has four A/V inputs and one A/V output. AV1-AV3 accept composite or S-video plus stereo audio inputs and these feed into the TV’s A/V output. AV4 accepts Component video (Y/Pb/Pr) plus stereo audio but unlike AV1-AV3, its audio (and video) signals are not fed to the TV A/V output. The Y/Pb/Pr input was chosen for use with the DVD player because of its superior video quality, while the audio was to be fed to an external amplifier for improved reproduction.

Circuit diagram:

Dual Input-Combining Stereo Line Amplifier Circuit Diagram

However, manual switching was inconvenient, hence the genesis of this design. In use, the DVD player audio is fed in parallel to TV AV4 and to one input pair of the combining amplifier, while the TV audio output feeds the other input pair. The amplifier output goes to the external audio amplifier. There is no conflict between the two audio inputs because when AV4 (DVD player) is selected, there is no TV audio output. In all other modes, the DVD player is off. As shown, the circuit has a voltage gain of 1.5 times (3.5dB) but this can be altered as required by changing the two 15kW resistors. Input impedance is 10kW and the outputs are isolated from cable and amplifier input capacitance with 47W series resistors. The circuit can be powered from a regulated 12V DC plugpack.

Author: Garth Jenkinson - Copyright: Silicon Chip Electronics

Source : www.extremecircuits.net

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HQ Notch Filter Without Close Tolerance Components

A notch for a narrow frequency band of a few per cent or even less normally requires close-tolerance components. At least, that’s what we thought until we came across a special opamp IC from Maxim. In filters with steep slopes, the component tolerances will interact in the complex frequency response. This effect rules out the use of standard tolerance components if any useful result is to be achieved. The circuit shown here relocates the issue of the value-sensitive resistors that determine the filter response from ‘visible’ resistors to ready available integrated circuits which also make the PCB layout for the filter much simpler. The operational amplifiers we’ve in mind contain laser-trimmed resistors that maintain their nominal value within 1‰ or less. For the same accuracy, the effort that goes into matching individual precision resistors would be far more costly and time consuming. The desired notch (rejection) frequency is easily calculated for both R-C sections shown in Figure 1.

Figure 1. Special opamps incorporating laser-trimmed resistors.

Dividing the workload:

The circuit separates the amplitude and frequency domains using two frequency-determining R-C networks and two level-determining feedback networks of summing amplifier IC2, which suppresses the frequency component to be eliminated from the input signal by simple phase shifting. IC1 contains two operational amplifiers complete with a feedback network. The MAX4075 is available in no fewer than 54 different gain specifications ranging from 0.25 V/V to 100 V/V, or +1.25 V/V to 101 V/V when non-inverting. The suffix AD indicates that we are employing the inverting version here (G = –1). These ICs operate as all-pass filters producing a phase shift of exactly 180 degrees at the roll-off frequency f0. The integrated amplifier resistors can be trusted to introduce a gain variation of less than 0.1 %.

They are responsible for the signal level (at the notch frequency) which is added to the input signal by IC2 by a summing operation. However, they do not affect the notch frequency proper — that is the domain of the two external R-C sections which, in turn, do not affect the degree of signal suppression. In general, SMDs (surface mount devices) have smaller production tolerance than their leaded counter-parts. Because the two ICs in this circuit are only available in an 8-pin SOIC enclosure anyway, it seems logical to employ SMDs in the rest of the circuit as well. Preset P1 allows the filter to be adjusted for maximum rejection of the unwanted frequency component.

Figure 2. This deep notch is within reach using just 5%-tolerance resistors and 20%-tolerance capacitors.

R-C notch filter:

Using standard-tolerance resistors for R1 and R2 (i.e., 1%, 0806 style) and 10%-tolerance capacitors for C1 and C2 (X7R ceramic) an amount of rejection better than that shown in Figure 2 may be achieved. The notch frequency proper may be defined more accurately by the use of selected R-C sections. Pin 3 of IC2 receives a signal that’s been 90-degrees phase shifted twice at the notch frequency, while pin 1 is fed with the input signal. These two signals are added by way of the two on-chip resistors. IC2 is a differential precision operational amplifier containing precision resistor networks trimmed to an error not exceeding ±0.2‰. Here, it is configured as a modified summing amplifier with its inverting input, pin 2, left open.

For frequencies considerably lower than the resonance frequency f0 = 1 / (2 π R C) the capacitors present a high impedance, preventing the inverting voltage followers from phase-shifting the signal. At higher frequencies than f0, each inverting voltage follower shifts its input signal by 180 degrees, producing a total shift of 360 degrees which (electrically) equals 0 degrees. The phases of each all-pass filter behave like a simple R-C pole, hence shift the signal at the resonance frequency by 90 degrees each. The three precision amplifier ICs can handle signals up to 100 kHz at remarkably low distortion. The supply voltage may be anything between 2.7 V and 5.5V. Current consumption will be of the order of 250µA.

Source : www.extremecircuits.net

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Discrete Robot

This simple robot, which responds to light and avoids obstacles, can be built without using a microcontroller, programmer or PC. The only ‘special’ component in the circuit is a window discriminator (a fancy version of a window comparator). Resistors R1 and R2 in combination with light-dependent resistors LDR1 and LDR2 form a voltage divider (with the current being limited by R1 and R2 for bright light). Window discriminator TCA965 compares the mid-point voltage with an upper threshold value (adjustable using P1) and a lower threshold value (adjustable using P2). Outputs AU, AI, AO, and AA go High if the voltage lies below, inside, above or outside this window, respectively; otherwise they remain Low.

Output AA switches transistor T1, which drives the right-hand motor. The light-dependent resistors can be attached on the left and right sides of the vehicle, or at the front and rear. This causes the robot to turn to the right, due to the motor on one side being stopped, until the desired lighting relationship is restored. The vehicle will then continue to travel in a straight line until the lighting relationship again changes, at which point it will again turn, and so on. You can experiment with various behaviour patterns by using the other outputs of the window discriminator. If a transistor is provided for each of the AU and AO outputs of the TCA965, the robot can be made to travel toward or away from a light source, depending on the connections.

Using the window discriminator, the robot will operate under the rules of a three-point controller (left, straight ahead, or right). If you fit the light-dependent resistors in a box under the vehicle together with a light source, you can try to have the robot follow a black line on a white background. A reflective IR sensor enables the robot to respond to obstacles. This not as simple as it might seem, since the Sharp IS471 operates the IR LED with pulsed light and uses sophisticated detection processing. When an obstacle is detected, the output (pin 2) goes Low and blocks transistor T2. This causes the motor to stop, and the vehicle will rotate about the stationary wheel until the obstacle is no longer in its path.

The sensitivity of the IS471 can be set using P3. As its range is only around 10–15 cm, the vehicle must not travel too quickly, since otherwise it will not be able to avoid obstacles in time. This part of the circuit is also open for experimentation. If a relatively large and fast robot requires an obstacle detector (or isn’t fitted with the IS471), an ultrasonic detector can also be used. Suitable complete construction kits are available from Conrad, for example. You can also fit a suitable mechanical push-button switch mounted on a flexible rod. The obstacle detector can also drive a warning buzzer or a lamp; the circuit leaves lots of room for your own ideas. The circuit works over a wide range of supply voltages from 4.5 to 16 V.

If larger motors are used, transistors with increased power-handling capacity and heavier batteries are necessary. The author connected two 4.8-V rechargeable batteries in series and used BC388 transistors as drivers for Lego micro-motors. You can build the robot entirely according to what you have in your parts box. The mechanical elements can also be freely selected, but they partially determine the behavior and operation of the robot. The author’s robot is made from a Lego chassis with a prototyping board holding the circuitry attached using elastic bands. The motors are fitted on the left-hand and right-hand sides. The third wheel at the front can turn freely.

One problem must be mentioned: if an obstacle is detected while an incorrect lighting relationship is present, the vehicle remains standing. In this case, a bit of logic could be added to cause both motors to rotate in reverse. However, that would require directional switches for the motors or motor driver ICs (L293D). The simple circuit would become more complicated and larger, and at some point you would end up using a microcontroller after all - but that’s just the point of the story.

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RESISTOR TO REDUCE L200 POWER DISSIPATION ELECTRONIC DIAGRAM

RESISTOR TO REDUCE L200 POWER DISSIPATION ELECTRONIC DIAGRAM

Instead of in series with the input, the resistor R can be connected between pins 1 and 2 of the IC if the load is constant. You can see this in the right figure. This will make some part of the load current flows through the resistor and the other part through the device.

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Speaker Headphone Switch For PCs

If you need to use a headset with your PC, then you will know how frustrating it is continuously swapping over speaker and microphone cables. This is even worse if the PC is parked in a dark corner and the hard-to-read writing on the sound card sockets is covered in dust. This simple switch box eliminates all these problems. It sits on top of the desk and connects to the PC with stereo one-to-one cables. On the rear of the box are sockets for the PC speaker and microphone connections and the existing speakers. On the front of the box are the sockets for the headset microphone and headphones, an input for an external microphone and two switches. One switch is used to direct the sound card output from the PC to either the existing speakers or the headphones.

Circuit diagram:

Speaker-Headphone Switch Circuit Diagram For Computers

The second switch connects either the headset microphone or the external microphone to the input socket of the PC sound card. The switches used were 3 position 4 pole rotary switches with the last pole unused and adjusted for 2-position operation. All sockets were stereo 3.5mm types. This multiple switching arrangement is very flexible and is especially handy if you want to use an external microphone while monitoring with headphones. The ground wire as well as the left and right wires are all switched to prevent noise that could otherwise be induced into the microphone input through joining separate earths. For the same reason, a plastic case is used so that the earths of the sockets are not shorted together as would happen with a metal case. You will require two additional short stereo extension cables to connect the box to the PC.

Author: Leon Williams - Copyright: Silicon Chip Electronics

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Up Down Fading LED Circuit

This circuit drives a motor clockwise / anticlockwise via a pot and reduces the speed to zero when the pot is in mid-position. The current is limited to 200mA and the voltage across the motor is less than 6v, but the circuit shows the principle of Pulse Width Modulation (providing powerful bursts of current to the motor to create a high or low RPM under load) and both forward/reverse RPM via the H-bridge arrangement.

Circuit diagram:

 Up/Down Fading LED Circuit diagram

 

Source : 50-555Circuits

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Alarm Clock With Day Selector

This  circuit disables an alarm clock on Saturdays and Sundays when people like to sleep in but enables normal operation on Mondays to Fridays so that people rise in time for work or school. The core of the circuit is a 4017 decade counter which acts as the day counter and it is used in conjunction with a desk clock which acts the alarm and a watch module with alarm function which provides one clock pulse very day to the 4017. In operation, the watch module feeds a day pulse via transistor Q3 to the clock input of IC1. This has seven outputs connected via day switches (S1-S7) and diodes D3-D9 to Q1 which disables the alarm signal to the speaker via transistor Q2. LEDs1-7 indicate the actual day (if you forget!).

Circuit diagram:

Alarm Clock With Day Selector Circuit Diagram

To set the system, set the desk clock for the correct time and for the desired alarm time (eg, 6’o’clock). The watch module is set to the correct time and its alarm set to midnight. The day counter, IC1, is set to the correct day, as indicated by the LEDs, by pushing switch S12 and closing switch S8 or S9. S8 is normally left open to conserve the battery by leaving the LEDs off. As shown on the circuit, switches S1-S7 are set to sound the alarm on Mondays to Fridays and disable it on Saturday and Sunday. However, you can change the days to suit your work habits.

Author: Rasim Kucalovic - Copyright: Silicon Chip Electronics

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1963 Dodge Dart Electrical Wiring Diagram

1963 Dodge Dart Electrical Wiring Diagram

The Part of 1963 Dodge Dart Electrical Wiring Diagram: direction signal switch connector, cigar lighter, ammeter, heater blower switch, the stop light and direction signal, tail light, beam selector switch, light switch, luggage compartment, circuit breaker, gas gauge, backup light, printed circuit connector, parking brake warning light and switch, etc. Features: lower-priced, shorter wheelbase, full-size Dodge.

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1999 Lincoln Continental Wiring Diagram

1999 Lincoln Continental Wiring Diagram

The Part of 1999 Lincoln Continental Wiring Diagram: fuse junction panel, autolamps, multifunction
switch, hazard, lighting crtl module, shift lock actuator, hazard flasher, switch input, stoplamp, passenger, delaved exit, turn left/right

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