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| MOC3041 BTA26 strange behavior |
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| gj.gj:
Hi, I am trying to build a fairly simple circuit but it is behaving in a very strange way. fig2.png is the schematic. When I connect R10 the triac conducts immediately despite the optocoupler state. Without R10 the triac does not conduct but the opto is not able to drive it even though the pin 1 and pin 2 are controlled correctly with 10-20mA through the diode. Any help to troubleshoot is welcome. |
| wraper:
--- Quote ---When I connect R10 the triac conducts immediately despite the optocoupler state. Without R10 the triac does not conduct but the opto is not able to drive it even though the pin 1 and pin 2 are controlled correctly with 10-20mA through the diode. --- End quote --- You connected the triac a wrong way around. Swap A1 and A2 pins. |
| matseng:
--- Quote from: wraper on June 02, 2018, 12:04:38 pm ---You connected the triac a wrong way around. Swap A1 and A2 pins. --- End quote --- Would that really matter for a four-quadrant triac? |
| wraper:
--- Quote from: matseng on June 02, 2018, 02:57:14 pm --- --- Quote from: wraper on June 02, 2018, 12:04:38 pm ---You connected the triac a wrong way around. Swap A1 and A2 pins. --- End quote --- Would that really matter for a four-quadrant triac? --- End quote --- It matters for any triac. You cannot just switch the terminals around. Voltage on gate should always be applied in reference to A1(MT1) pin. |
| matseng:
Hmmm... Yes that seems reasonable. It was 35+ years since I read up about the workings of triacs so I forgot most of it - [ Teh old people are stupids ;-) ]. But it's slowly coming back to me now. Thanks. |
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