DC-DC Convertor with Operational Amplifier
Électronique / Electronic
NE5532

Here's a DC-DC converter circuit; it can gain 5V DC from 3V DC.

Build the project, set the switch to position ON, and see how this circuit works.

Look at the schematic. IC 1 acts as an oscillator. The output of IC 1 turns on transistor Q1.

Self-induction of the transformer coil instantly generates a high voltage current.

Diode D1 rectifies this voltage and passes on a high DC voltage current.

IC 2 is a comparator that examines the voltage increase. When the input voltage to IC 2 is more than 5V, the LED lights.

By the way, did you try rotating the control? How does it affect the circuit?

In this circuit the control is used as a fixed resistor of 50K ohms. Rotating the control has no effect.
(Sorry if we had you worried.)