This circuit is from Motorola's 1990 Linear Databook. The transistors allow equivalents and the output power depends on the supply voltage. The power supply must be 30 V symmetrical.
This stage with polarization of only one resistor can use any general-purpose transistor. The...
This voltage-controlled potentiometer using an LDR was found in an English documentation. LDR is...
This interesting sensor for RF signals was found in an article in the June 1989 Radio Electronics...