I'm trying to use an optoisolated (MOC2031) triac (BT137) to drive resistive loads up to a few 100W (light bulbs for incubator heating). The output to drive the MOC input is 6v as the output of a 555 timer. This is in series with 360ohm to the MOC2031. On the power side the hot 240v line goes to pin1 of the the triac and a 360 ohm 1/4W resistor to pin 6 of the MOC. Pin 2 of the triac is connected to the other hot wire which goes to the load (currently 150W bulb).
Pin 3 of the MOC is connected direct to pin 3 of the triac. This seems to copy the circuit shown on the fairchild data sheet for the MOC, without the snubber components. But the triac does not turn on. There is about 20mA going through the input LED of the MOC.
Am I missing something obvious?
Pin 3 of the MOC is connected direct to pin 3 of the triac. This seems to copy the circuit shown on the fairchild data sheet for the MOC, without the snubber components. But the triac does not turn on. There is about 20mA going through the input LED of the MOC.
Am I missing something obvious?