Found in an Electronic Design from the 90's, this circuit indicates three voltage levels by activating the LED in 3 modes: off, flashing and on for high voltage.
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...