This converter or inverter uses components that are still common. The transformer is the type found in old tube equipment. The power transistors must be mounted on heat radiators.
This circuit detects light variations using two LDRs as sensors. Operational amplifiers and...
The circuit shown consists of a power stage for relay excitation. 2N3053 can be a BD135 and 2N406...
This circuit was found in Mullard's 1960s transistor manual. The circuit uses germanium...