This alarm circuit triggers when S1 opens. The circuit from a January 1975 Radio Electronics magazine can be used with interrupt sensors connected in series.
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...