This circuit was found in an American documentation from the 80's. The components are from that time. It provides a variable output of 18 to 30 V with a current of 200 mA.
This circuit can be used as a control shield for microcontrollers of all types. The supply is made...
The figure below shows an AC transconductance amplifier with the National Semiconductor LM3900. The...
This circuit provides a good audio power from a signal at least 1 V of amplitude. The MOSFET must...