We found this solid-state relay circuit that can function as a shield in a Radio Electronics magazine from December 1989. The optocoupler is a phototransistor type.
This circuit generates signals that depend on Ct and the 10k trimpot adjustment. See the math...
This circuit was found in a 90s 303 Circuits. The circuit operates in a 200 Hz switching mode and...
The circuit presented was obtained in a technical documentation from National Instruments. The...