This alarm circuit with sensors in series was found in the Electronics Now magazine of June 1994. The circuit is powered according to the relay used.
This oscillator with FET was found in Popular Electronics from the 90s. This traditional...
This is a traditional complementary-output transistor amplifier sourcing 2 to 4 watts to a 4 ohm...
This circuit was found in the July 1992 issue of Radio Electronics magazine. The circuit is based...