Found in a 90s Popular Electronics, this circuit checks if a remote-control transmitter is emitting signals. The sensor is a general-purpose type found in many electronic devices.
This simple circuit for motors that depends on the MOSFET used was found in the January 1998...
This transistorized shield also functions as a logic gate. The power supply can be in the range of 4.5...
Found in a 90s Popular Electronics, this Hartley oscillator uses an output transformer of the type...