This transistorized circuit appeared in a Radio Electronics magazine in March 1958. The frequency range depends on the tuned circuit, being within a few megahertz.
We found this configuration in a 1974 technical documentation. It can test both TTL logic circuits and...
This circuit emits an alert sound (interval beeps) if the car lights are left on and the ignition key...
This is an amplifier that uses a pickup coil placed next to the telephone set and the listening is done in...