With this circuit it is possible to modulate pulses from a pulsating input signal. The PNP transistor can be the BC558 and the power must be supplied with 5 V.
This decoder for FSK modulated signals can operate at frequencies of 10.8 MHz. We find it in...
We found this circuit in a 1965 publication by General Electric. The zener is 8.2 V x 1 W and the...
Found in an Electronic World, this circuit is designed to control solenoids up to 5 A. The circuit...