Power supply circuit has a first amplifier using op-amp is IC uA741. Op amp circuit that is used only one, but it also features an adjustable voltage, which is steered by a trimpot resistors. Rtrim will set the input to the IC input on pin 2, so that if the detainee on Rtrim which will be channeled into ic enlarges the output voltage will be small, and otherwise. After the voltage is boosted and filtered and then the voltage will be regulated and boosted again by a NPN transistor.
|Output voltage 0.5V - 35V|
U1____uA741 (op-amp ic)