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 amplifier for sound equipment was found in the Philips Databook of 1990. The circuit can be...
I found this circuit in an English publication from 1989. This configuration can be mounted with...
The circuit shown is from a 1978 Texas Instruments optoelectronics manual. The circuit can use...