Using an operational amplifier of the time, this circuit was obtained from a 90s Radio Electronics. The circuit covers the frequency range from 2 Hz to 20 kHz.
This circuit is like the previous one except that it can be triggered electronically. The circuit is...
Found in 90s Radio Electronics, this audio indicator makes use of an integrated circuit that is...
Found in the October 1992 Radio Electronics magazine, this oscillator is controlled by switch S1....