This circuit is from 1980s documentation. The maximum operating frequency is 3.5 MHz. The current of the LED can be from 0 to 100 mA. The integrated circuits used are from that time.
The purpose of this interesting circuit found in a 1977 documentation is to complete the last...
The optocoupler in the figure uses common transistors and a phototransistor to drive a sensitive relay...
The coil consists of 100 turns of wire 28 in a wooden or PVC tube from 2 cm to 2.5 cm in diameter with...