This small control for DC motors up to approximately 1 A uses an operational amplifier that admits equivalent. The transistor can be TIP29 for currents up to 1 A or BD135 for 500 mA.
The figure shows a remote-control receiver working the 27 MHz band, very popular in the 60’s. The...
This 1 MHz oscillator was found in an Electronics World of 1969. The circuit uses a...
This circuit was found in an old documentation. It converts DC voltages and its maximum current...