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 was found in a 1982 documentation. It uses only one integrated circuit and can be...
Only those who know the secret activation code will be able to turn on the device connected to...
This 2 meter (144 MHz) preamplifier is intended for use with portable transceivers. The...