This circuit can be used as an answering password system in a store, office, or other location. The circuit is from Intersil using components of the time. The circuit is from the 80's.
In the figure we have a practical circuit for a 50 kHz bandwidth amplifier using a photo diode as...
This circuit consists of a small inverter that can generate a few hundred volts of DC voltage...
Found in a 1967 Electronic Design, this transistorized circuit compresses and then expands a pulse....