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 old configuration of an audio amplifier has a push-pull two-transistor output stage. Output...
This is the traditional configuration of na Astable Multivibrator using two NPN ttransistor....
This circuit is from 1987 documentation. The operating system used is not common today, but two...