This circuit generates rectangular signals from 2 Hz to 20 kHz using an operational amplifier. The circuit is from 1984 Radio Electronics. The power supply must be symmetrical.
This circuit uses old germanium transistors because it was found in an old magazine from 1973....
This logic level indicator also indicates the presence of pulsating signals through a third LED. It...
This circuit is from the 1990 Motorola Linear Databook, which can be developed with more modern...