This circuit uses an optocoupler with a phototriac or optotriac to drive an external triac. The circuit is from a Radio Electronics magazine from December 1989.
This circuit was found in an American documentation from the 80's. The components are from that...
Three LM158, LM258, LM358, or LM2904 operational amplifiers are used in this instrumentation amplifier....
I found this circuit in a 1992 Electronics Experimenter Handbook. The circuit can be easily...