The presented circuit makes use of a common operational amplifier that must be powered by a symmetrical source. R resistors from 10k to 1M determine the gain and compression of the signal.
This is the single-sourced version of the previous oscillator. Frequency can be changed by...
This is a commercial circuit found in Radio Electronics magazine from September 1960. The circuit has...
This circuit is from a 1998 Poptronics. The circuit triggers a buzzer after a certain time, waking...