This circuit that generates signals between 1.5 and 2 kHz was found in a documentation from the 90's. The capacitor C1 can be changed to obtain other frequencies.
This circuit is from European documentation from the 1980s. The circuit consists of an R-S...
Found in the documentation on PCs, this circuit excites LEDs whose current is determined by R3....
This simple SCR relaxation oscillator was indicated by a 90s Popular Electronics. The frequency is...