Found in an EDN from the 1980s, this circuit uses a double 555. The circuit activates a relay that controls a horn or siren. Next to the diagram we have the timings.
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...