If you are looking for a simple power supply circuit with PCB. This is the Variable power supply circuit using IC-741. It was a famous IC-op-amp for a long time ago. This electronics age still is useful.
We have many the simple variable power supply circuits. Here is another idea. If you have old components in your store. You can turn to use it again.
This circuit can give you many things. First, the output supply voltage range: 0 volts to 30 volts. Second, the output current maximum: 2A (requires 2A transformer). Third, Overload protection with LED display.
How it works
Look in 0-30V, 1A, Variable power supply using IC-741,2N3055, and 2N3565
First, the input of circuit plugs into the wall and converts the high-voltage AC supply in your home into a safe, low DC voltage for electronic devices.
The 220V AC mains voltage from the power core comes into the transformer via a fuse to protect the circuit.
The transformer converts high voltage AC to lower voltage AC, 26V CT (26V-OV-26V).
Second, both power diodes are a full wave rectifier to rectify the AC to DC, varying DC voltage. Then, the 1000uF-filter capacitor smooths it into a steady direct current (DC). This is the unregulated power supply, at DC voltage about 36V.
Third, This circuit has a filtering regulator. They include many components. The IC-741 keeps the stable output voltage. The potentiometer-1K adjustable output voltage. The IC-741 makes a constant voltage out of pin 6. Then, flows to the base of CS9013 driver transistor to a 2N3055 power transistor with high current up to 2A. While it is working, it too hot so it requires the large heatsink.
Note: This circuit may be just a circuit idea. If you will build it. My thinking it has another choice. It is suitable for you.
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