Circuit Project Electronic

Simple Adjustable Voltage Source
Thursday, May 28th, 2009

A simple but less efficient methode of controlling a DC voltage is to use a voltage divider and transistor emitter follower configuration. The figure below illustrates using a 1K pot to set the base voltage of a medium power NPN transistor. The collector of the NPN feeds the base of a larger PNP power transistor [...]

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Dual Polarity Power Supply by LM317-LM337
Sunday, May 24th, 2009

This dual polarity power supply is easy to build, requires few parts, and is adjustable from 0-15 volts. It is great for powering op amp circuits, as well as other circuits that require a dual supply voltage.
# Since this project operates from 120 (or 220, or 240, etc.) volts AC, it MUST be built inside [...]

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0-30 V DC Power supply with current control 0.002-3 A
Sunday, May 24th, 2009

This is a high quality power supply with a continuously variable stabilised output adjustable at any value between 0 and 30VDC. The circuit also incorporates an electronic output current limiter that effectively controls the output current from a few milliamperes (2 mA) to the maximum output of three amperes that the circuit can deliver. This [...]

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