Based on the LF256 operational amplifier, this circuit was found in the September 1989 issue of Radio Electronics magazine. The indicator is analog, and the power supply must be symmetrical.
This circuit consists of a traditional version amplifier with complementary output transistors...
This circuit is from a manual of linear integrated circuits of the 80s. The operational is of the...
Also suitable for use as a noisy alarm, this Morse Code or telegraph practice oscillator was found...