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Simple Adjustable DC Power Supply
This project is a variation on those using linear voltage regulator chips to power low-voltage experiments wherein it uses a low dropout regulator to allow lower input voltages and a fine adjustment system.
For details about what capacitor values should be used and how to wire an adjustable regulator circuit, the datasheet for the regulator should be checked. A second variable resistor was added for fine adjustment instead of a single one to adjust the voltage. The voltage depends on the sum of two resistors in series and will change the output voltage slowly by adjusting the fine control which possess lower resistance.
Two large pins are used by the most common style of DC power jacks which are too wide to fit in standard perfboard holes. The holes in the board must be cut wider to be able to mount the jack. A switch in the circuit uses a third terminal on the jack but it can be bent out of the way of have it cutoff since the circuit does not use that terminal.
TO-220 packages are used by the medium and high power linear regulators mounted on heatsinks.
Click here to see the rest of the project.