This circuit was found in documentation from the 1980s. The circuit uses several components of the time, which are uncommon today. We must not supply it with a transformerless power supply.
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...