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.
New SAMHA1GxxA Microcontroller Family Delivers Integrated Peripheral Touch Controller for...
In this circuit of an American publication of 1978, the integrated circuit may be the 4001 and the...
This circuit was originally designed to maintain the temperature of a brooder at 41º C. However,...