This circuit uses an optical coupler called Raystor created by Raytheon in the 1960s. The circuit uses components from the era that can be changed. The current is low.
This circuit is suggested by the Optoelectronics Sourcebook by Texas Instruments when AC signals...
This circuit was found in 80's Popular Electronics. Transistors are commonly used. The...
When the power is turned on, the output of this circuit goes to the “1“ logic level by a time...