Switching Power Supply Using the LMZ14202H

Using the LMZ14202H power switching controller, can be designed a very simple switching power supply circuit that can provide a fixed output voltage covering a wide range of voltages .

Switching Power Supply Circuit diagram

This power switching power supply electronic project will provide a fixed output voltage between 5 and 30 volt from an input voltage between 8 and 42 volt at a maximum output current of 2 ampere . This circuit project power supply require few external electronic parts and can be configured very easy . In the table bellow you can see components value that are required for different output voltage

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SW Receiver Using MK414

A Short Wave Receiver based on the MK484 (formerly ZN414) that includes the tropical bands and 49 metre bands.

SW Receiver Using MK414 Circuit Diagram

Notes:
The original data sheet for the MK414 states a maximum working frequency is around 4 MHz. SW transmissions are so powerful that this receiver will work well with signals up to about 6 or 7 MHz. The 10k resistor controls the operating voltage for the IC which is critical for good performance.

Coil Details:
The tuned circuit consists of a variable capacitor and fixed air spaced coil. For the coil, I wound between 10 and 20 turns of wire on an empty tube of around 1.5 inches diameter. The turns were spaced so that the overall length was around 3 inches. The variable capacitor tuned 0 - 300 pF but there is plenty of scope for experiment here. One final point, you will need an external antenna to receive broadcasts. I have an outside wire that is about 7 meters long and this was quite effective. The antenna can be connected at either end of the coil or via a series capacitor value between 10pF and 100pF.

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Economy Radar Detector Circuit

Circuit Diagram

Description

This circuit uses a 1458 dual op-amp to form a radar detector. C1 is the detector of the radar signal. The first op-amp forms a current-to-voltage converter and the second op-amp buffers the output to drive the piezo transducer. R5 sets the switching threshold of the second op-amp; normally it is adjusted so that the circuit barely triggers on background noise, then its backed off a bit. The response of the circuit may be tuned by adjusting the length of the leads on C1. For typical road-radar systems, the input capacitors leads should be about 0.5 to 0.6 inches long.

Author: "Radio-Electronics" Magazine, Jul,86 issue (C) Copyright Gernsback Publications, Inc., 1986
 Source http://www.electronics-lab.com/

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Voltage Rating Tester for Zener Diode

I have teamed up with Magazine Mikro Elektronica for this project. Please visit their site. I am very grateful to Aleksandar Dakic for the kind translation into Serbian and Romanian languages.

Voltage Rating Tester for Zener Diode Circuit Diagram

Notes:
Using a single 555 Timer IC and a small transformer to generate a high voltage, this circuit will test zener diodes of voltage ratings up to 50VDC. The 555 timer is used in the astable mode, the output at pin3 drives a small audio transformer such as the LT700. This has a primary impedance of 1K and a secondary impedance of 8 ohms. Used in reverse the unloaded ac voltage is around 120volts ac. This is rectified by the 1N4004 diode and smoothed by the 2.2u capacitor which MUST be rated at 150 VDC. The zener under test is measured with a multimeter set to DC volts as shown. The load current switch enables the zener to be tested at 1 or 2mA DC. The rectified DC load, but a good zener should maintain the reading on the volt meter.

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