This circuit was obtained from an Electronic Design from the 90's. The circuit generates signals at a frequency determined by R and C. The selection by the jumpers determines the PWM modulation.
This alarm goes off if someone leaves a door open. We found it in the Encyclopedia of Electronic...
The pulse duration is determined by the 100k resistor and the separation by the 1M resistor. The...
This circuit uses high voltage transistors to provide direct power from the 110 V power grid or a...