This ingenious circuit was found in a 1990s Popular Electronics. The oscillator is a 555 and the keyer uses an optocoupler in the configuration shown.
Found in a 1967 Electronic Design, this circuit can detect pulses as narrow as 0.2 us. Active...
This circuit has a monostable action with time given by the capacitor. The bipolar transistor can...
September 2017 - Texas Instruments TPS543C20 Step-Down Converters can be found on Mouser...