Triac control LED bulb flickering

Thread Starter

LOTUS_RATHOD

Joined Aug 23, 2019
7
Hi i am Lotus,
I make circuit of triac AC load control (on and off only) see attached file
I have some few question related to TRIAC control.
1. When I connect filament bulb then it's working fine but when connect LED bulb then bulb is flickering. I know because of latching current and holding current of triac but my question is how to remove it.
2. If i remove R3 and C1 then LED bulb is not flickering. Why ? and How?
3. Which type of resistor and capacitor can be use for snubber circuit (R3 and C1)? i want it SMD small size packeg.
4. Did i missing something important ?IMG_20190829_103304.jpg
 

danadak

Joined Mar 10, 2018
3,577
Does the LED bulb have a driver in it or does it look like a simple
R load ?

Regards, Dana.
 

DickCappels

Joined Aug 21, 2008
5,882
Following up on @danadak 's question, LED lamps come in "dimmable" and "non-dimmable" versions. Non0dimmable lamps are the most common. This probably the kind you have.
 

Thread Starter

LOTUS_RATHOD

Joined Aug 23, 2019
7
Thank you for replay DickCappels and danadak
The LED bulb is non-dimmeble and its have in built voltage down converter for small LEDs
 

Dodgydave

Joined Jun 22, 2012
8,389
You need a 1K resistor between G and MT1, to keep the gate off..Also put the load in the MT2 circuit series Live.

omit the R3,C1..
 

Thread Starter

LOTUS_RATHOD

Joined Aug 23, 2019
7
Dear Dodgydave and other my friends
Thank you for your advice but I can't remove R3 and C1 from circuit because of it's block high voltage and current transient.
And if i connect filament bulb then that transient will turn on the bulb for some milliseconds. So can't remove it.

I connect 1K resistor as you told. But LED bulb still blinking. I think it's blink because of R3 and C1 component.And when i remove R3 and C1 then LED bulb not blinking and work fine.May be i need to change R3 and C1 value.
 

ci139

Joined Jul 11, 2016
716
the link is to get there , the attached .txt contains the sim. to drop to Menu/File/Import From Text

the sim. showed that 9W "current lim" enables the triac to switch on near max amplitude + it'll produce a lot of heat with low loads ...
however with some modifications i now got the thing to simulate ...
 

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Thread Starter

LOTUS_RATHOD

Joined Aug 23, 2019
7
Dear ci139 thanks for the support.
I see the sim file and I have some doubts.
1. what is the op-amp and D flip-flop circuit do.
2. how you say " it produce lot of heat " I check with hardware and any component not get hot.
3. In practical when i remove snubber circuit then LED bulb not blink but in your simulation shown some current will flow in TRIAC after 100nF capacitor remove.Why ?
4. and my biggest question how to solve it ?(flickering of LED bulb) still didn't get it :(
And Please help me to select snubber circuit resistor and capacitor type.(i want to use SMD packeg).

Please Help Me :(:confused:
 

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