This sophisticated circuit with two LF411 operational amplifiers appeared in the November 1984 issue of Radio Electronics magazine. The circuit uses a Mallory buzzer as an indicator.
This circuit for analog video signals was found in old American documentation. The transistor...
This circuit was suggested by Motorola in 1980s documentation. The circuit employs an operational of...
This circuit is from an American cookbook from 1977. The circuit generates a voltage of...