This circuit is from a 1968 publication. Here we have several types of resistive sensors with individual adjustments triggering a single SCR. Power depends on the type of sound device to be triggered.
This circuit was found in the December 1977 issue of Radio Electronics magazine. The circuit uses...
We obtained this circuit from an old Argentine magazine. The circuit originally uses germanium...
The 78XX series voltage regulator integrated circuits do not support an input voltage greater than...