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.
In the figure we have the way of modulating or controlling the frequency of a relaxation...
The integrated circuit used in this regulator is not very common today. The circuit is from old...
We find this circuit in a 1977 technical documentation. The circuit generates signals in a wide...