Jason,


Forgot to mention that besides swapping MT1 and MT2, the load resistor
R2 must be moved to the other AC leg, together with MT2.


Cheer,

Isaac




Em 01/01/2016 22:40, Isaac Marino Bavaresco escreveu:
> Jason,
>
>
> The circuit is a little confusing. It seems that MT1 and MT2 should be
> swapped.
> Indeed the circuit seems to be simply wrong. MT1 is the reference pin
> and it is kept always more than 10 V above or below the GATE.
>
> TRIACs can be fired in all four quadrants, that is, the polarity of the
> current on MT2 or GATE respective to MT1 can be any combination, BUT it
> is more sensitive in quadrants I and III, and much less sensitive in
> quadrant IV.
>
> For simple AC circuits, the TRIAC is usually fired in quadrants I and
> III, but for digital circuits the circuit would be too complicated, and=20
> to avoid firing it in quadrant IV, it is usually fired in quadrants II
> and III.
>
> It seems that the original intention of the author was to fire it in
> quadrants II and III.
>
>
> Isaac
>
>
>
>
> Em 01/01/2016 21:56, Jason White escreveu:
>> Hello,
>>
>> I am a student, I saw this low voltage TRIAC driving circuit on the
>> internet and am puzzled as to why it uses a negative voltage rail?
>>
>> As far as I know, TRIACS are not sensitive to the polarity of the signal
>> applied to the gate (with respect to MT1). Could this configuration work
>> with a positive supply (with respect to neutral) in all four quadrants?
>>
>>
>>

--=20
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