Found in a 90s documentation, this circuit appears in other configurations on this site. The circuit can be powered with voltages from 5 to 12 V.
This triac circuit was taken from an article in the July 1970 Radio Electronics magazine. Note the...
Signals ranging from a few millivolts to a few volts can be used to excite a relay with this...
This circuit was found in American documentation from the 90's. The transformer determines the...