This alarm with NO and NC sensors was found in the January 1975 Radio Electronics magazine. The circuit emits a powerful sound that depends on the output transistor.
This circuit monitors extra-low frequency (ELF) fields. We found it in an American documentation from the...
We can use any type of resistive transducer with central resistance in the range of 10 k ohms to 1...
This circuit controls two lamps so that when one increases in brightness the other decreases. The...