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 simple expandable circuit was obtained from a Popular Electronics from the 80's. The supply...
This traditional configuration found in a Radio Shack document can use 2N2646. More keys can be...
This circuit was obtained in an Argentine publication in 1976. It consists of a series voltage...