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.
The voltage gain of this amplifier is 10 times. This gain is given by the relationship of values...
We found this circuit in an American 1980s documentation, but it can be implemented with modern...
This ultra-simple test circuit is of great use in any electronics bench. The power is supplied by a...