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 latching alarm circuit using relays was found in American documentation. Sensors are...
Pressing and releasing S1 remains one of the neon lamps. Which one will be, it is not possible to...
Found in an Electronic Design, this small power source uses a battery as a voltage reference,...