This alarm with automatic shutoff was found in the April 1975 Radio Electronics magazine. The activation time is given by C1 and R3. The alarm uses series and parallel sensors.
The critical component of this project from a 1988 publication is the transformer. The final power...
September 2016 – At Mouser is available the new N channel MOSFETs PMGD175NEX from NXP for currents of 950...
This series motor control circuit was obtained from an old manual from the 80's. The SCRs must be...