This alarm circuit with NC sensors in series was taken from an article in Radio Electronics magazine from May 1971. The SCR can be any of the 106 series.
This circuit can be used in the car to convert the 12 V from the battery in 6 or 9 V up to 2 A....
In the figure we have the way to implement a monostable with an operational amplifier LM393. The...
In the figure we have the simple way of controlling a load or having a signal from an optical...