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rajbex

A Variable DC Power Supply for Electronics Hobbyists

A variable DC power supply is one of the most important tools for an electronics hobbyist. Most of

  1. rajbex
    A variable DC power supply is one of the most important tools for an electronics hobbyist. Most of the microcontroller based projects can be done with a fixed +5V supply but while testing various analog circuits you may require a varying voltage source. I have made one for myself using LM350 IC. The LM350 is an adjustable 3-terminal positive voltage regulator that can supply in excess of 3A over a 1.2V to 33V output range. They are exceptionally easy to use and require only 2 external resistors to set the output voltage. Here is a snapshot of my power supply unit.
    [​IMG]

    It has a nice analog voltmeter to display the output voltage and a 5K potentiometer to vary the voltage. The circuit to control the output voltage is very simple, and is available in the datasheet on LM350 IC.
    [​IMG]
    The Vin can be connected to an unregulated DC voltage obtained from a step-down transformer through bridge rectifier. I set the values of R1 and R2 so as to get variable DC voltage ranging from 1.25-18V. For more details of this project, visit here.
    http://pic16f628a.blogspot.com/2010/07/variable-dc-power-supply-125-18v-using.html

    I hope you will like it.
    - Raj