This circuit was found in a 1970s General Electric documentation. This circuit already used an emitting LED. The circuit operates at frequencies from 50 Hz to 50 kHz with short pulses
We found this circuit in April 1979 Radio Electronics magazine. The circuit is based on the 555...
This circuit was found in a Popular Electronics from the 90s. The circuit uses general purpose...
This 80's circuit uses an integrated amplifier of the era, but nothing prevents it from being...