Found in a 90s Popular Electronics, this circuit uses a 741 to generate frequencies from 0.1 to 30 Hz. Observe the phototransistor feedback.
June 2017 - Mouser's new AQZ series solid state relays with switching capacity from 5A to 200V are now...
By activating S1 the relay closes its contacts only after a certain time interval that depends on C1....
The current accross the LED as function of the resistor value is given by the formulas. The...