This circuit was obtained in a 1967 Raytheon manual. The company's component is an optical coupler with a photo-resistor and a lamp. Transistors support equivalents.
Found in an American documentation, this circuit shows how an interface should be made for...
One touch of the push button S1 and the circuit LEDs shown in the figure start to flash rapidly. The...
In the figure we have an RF amplifier for tunnel diode. The frequency range will depend on the...