5 to 15V Regulated Power Supply Rise

Regulated Power Supply

This project is a normal DC regulated power supply that is a variable DC voltage range from 5V to 15V. It can supply current up to  400mA to power the various circuits for your electronic projects. The voltage output is varied by using the potentiometer V.R1. In this circuit, the input line power supply is designed for 240V.A.C. If 110VAC input is used, alter the ratings of the varistor to 150VAC & the transformer ratio to 110V/12V. 

Fuse F1 is used as a protection in case theres any short circuit in the circuit. Varistor V1 is connected in parallel to the input of the line voltage to clamp the surge voltage from the line to a reasonable level that helps to protect the transformer & other circuitry. One time the voltage level surge to a high level beyond the ability of the varistor to absorb it, fuse F1 or varistor V1 or both will burn. If this circuit failed after a period of operation, check that the fuse & the varistor are still in nice condition or else replace them.

Diodes D1, D2, D3 and D4 are used to rectify the 12V.A.C voltage to DC voltage. Electrolytic capacitor E1 is used as a smoothing capacitor to reduce the ripple of the DC voltage. The DC voltage is fed in to the input of 7805 regulator where the output DC voltage is obtained. Changing the worth of VR1 will alter the output of the DC voltage. Capacitor C1 is used to filter out high frequency part from the power supply.

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5 band graphic equalizer using a single IC chip

The BA3812L is a five-point graphic equalizer that has all the required functions integrated onto one IC. The IC is comprised of the five tone control circuits and input and output buffer amplifiers. The BA3812L features low distortion, low noise, and wide dynamic range, and is an ideal choice for Hi-Fi stereo applica-tions. It also has a wide operating voltage range (3.5V to 16V), which means that it can be adapted for use with most types of stereo equipment.

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5 3W Amplifier With Surround System

The AN7147 Dual 5.3-watt Audio Power Amplifier from Panasonic is listed as a ‘replacement type’ so hopefully will be around for some time to come. Together with some extra components, it can represent a simple surround-sound system requiring no opamps or a negative voltage supply. As shown by the circuit diagram the basic stereo amplifier is changed into a surround-sound system by a trick called ‘adding feedback from the opposite channel’. When surround sound is required, the negative feedback signals supplied by C13-R3 and C12-R4 are fed to the inputs of the ‘other’ amplifier. The resulting phase difference causes the surround effect. If surround sound is not required, the effect can be disabled by pressing push-button S1.

Circuit diagram :

5.3W Amplifier With Surround System Circuit Diagram

This causes the bistable built around IC2.A and IC2.B to toggle and drive transistors T1 and T2 such that the above mentioned negative feedback signals are effectively shunted to ground. A high-efficiency LED and a 3.3-kΩ series resistor (R14) should be used to make sure the maximum output current of the CMOS 4001 device is not exceeded. The amplifier should not be loaded with impedances smaller than 3Ω. The AN7147 will typically supply up to 4.3 watts into 4 Ω. The SIL-12 case needs to be cooled wit a small heatsink of about 6 K/W or better. The quiescent current is modest at just 19 mA.

Source : www.extremecircuits.net

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