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 is a circuit for testing small lamps and LEDs. The lamps that can be tested are the ones...
This circuit, also suggested by Texas Instruments, uses a photo diode in the reception and a field...
This is one of those circuits that the designer often looks for, but has trouble finding. Its...