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.
Radio Electronics magazine published in a 90's issue this simple alarm that can use any general...
This simple circuit tests electrolytic capacitors from 1 uF with a working voltage above 12 V. The...
This circuit was found in a 1967 Raytheon optoelectronics manual. The circuit uses tubes. | Clique...