In this scheme, adjustable voltage regulator IC 78L05 is used in conjunction with the integrated audio amplifier TDA2030 . Because of this, the stabilizer was very simple. The output voltage is regulated to 20 V with maximum current of 3 A. IC TDA2030 is protected against overheating and short circuits, making it a very reliable regulator.
This scheme is very simple. Besides the two chips, stabilizer actually contains only two potentiometers and several capacitors.
Adjustment is as follows: first, the engine turns potentiometer P1 to the maximum (in the direction of IC 78L05), and then the trimmer P2 is set to the desired maximum output voltage. Subsequently, the potentiometer P1 is used for fine adjustment of output voltage from this maximum value and practically to 0.
For a relatively small output current sink for cooling is not required. However, when the output current exceeds 1 A, or if the difference between input and output voltage is high enough, the amplifier IC2 will overheat, and a small heat sink is definitely needed.