The circuit presented was suggested by Texas Instruments in an opto-electronics manual. The transistor can be the BC548 and the supply voltage depends on the application.
In this 2001 circuit we have the way to trigger an SCR with a phototransistor. The circuit appears...
The operational amplifier used in this circuit of an old documentation no longer exists, but the...
This circuit, found in an old 1967 publication, cuts the current from a source when the current...