manoj.patil.1974
New Member
Hi, I have spent sleepless nights on this simple circuit that refuses to work. Can some one please help with with what's going wrong here ?
I am using a 230V A/C, 100W filament bulb as a load.
-> S2 on , bulb is not switched.
-> S2, S3 on, bulb is on and dimmed
-> S2, S3, S4 on, bulb is on and more brighter.
-> S1 on or off has no effect on the bulb brightness.
I googled and this circuit appears in many places and instead of R4,R5,R6 a 220K or 470K pot is used. However, in my experience, the bulb does not light up if R4+R5+R6 is more than 33K.
Also, R4,R5,R6 get hot. My question is why do I require so low value resitors (< 33K) for my circuit when everyone is able to handle it with 470K pot's ? I actually want to use a pot and want to have multiple dimmings settings.
R1 and R2 get very hot too. May be I should use 33K 1W or 15K, 4W resistors.
Here are my some debugging attempts
-> Instead of R4,R5,R6 I used a 16mm 470K pot and it smoked. I tried a 23mm 470K pot and it fumed too. Both were carbon pots. Should I try using 470K wire wound pots ? Problem is wire wound pots are not available for values greater than 100K
-> The capacitor has 100n written on it. I assumed its 100 nano farads. I even tried with a capacitor with 0.22 uf written on it. No change in behaviour
-> I have built this circuit atleast 5 times with FRESH NEW components.
-> Does it matter how I connect the Main Terminal 1 and 2 of the triac ?? Some websites state that it does matter but I thought these days triacs are reliably symetric.
Not sure what is going wrong here ? Are the BTA12 faulty or not behaving as per design ? These days the market is flooded with cheap chinese components hence its difficult to differentiate the real authentic ones with the fakes one's.
I am using a 230V A/C, 100W filament bulb as a load.
-> S2 on , bulb is not switched.
-> S2, S3 on, bulb is on and dimmed
-> S2, S3, S4 on, bulb is on and more brighter.
-> S1 on or off has no effect on the bulb brightness.
I googled and this circuit appears in many places and instead of R4,R5,R6 a 220K or 470K pot is used. However, in my experience, the bulb does not light up if R4+R5+R6 is more than 33K.
Also, R4,R5,R6 get hot. My question is why do I require so low value resitors (< 33K) for my circuit when everyone is able to handle it with 470K pot's ? I actually want to use a pot and want to have multiple dimmings settings.
R1 and R2 get very hot too. May be I should use 33K 1W or 15K, 4W resistors.
Here are my some debugging attempts
-> Instead of R4,R5,R6 I used a 16mm 470K pot and it smoked. I tried a 23mm 470K pot and it fumed too. Both were carbon pots. Should I try using 470K wire wound pots ? Problem is wire wound pots are not available for values greater than 100K
-> The capacitor has 100n written on it. I assumed its 100 nano farads. I even tried with a capacitor with 0.22 uf written on it. No change in behaviour
-> I have built this circuit atleast 5 times with FRESH NEW components.
-> Does it matter how I connect the Main Terminal 1 and 2 of the triac ?? Some websites state that it does matter but I thought these days triacs are reliably symetric.
Not sure what is going wrong here ? Are the BTA12 faulty or not behaving as per design ? These days the market is flooded with cheap chinese components hence its difficult to differentiate the real authentic ones with the fakes one's.
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