kiranlaleu
Junior Member level 1
I had made a circuit to turn load on and off using a TRIAC.
It all worked fine until the load was resistive or inductive.
As soon as I connected a LED lamp to the circuit all problems started coming in to the circuit. When the TRIAC was off. The LED lamp started to flash every few seconds with each flash becoming
brighter than the one before it.
So when I read about it in eevblog forum. I found a post where Mr. SeanB had said " LED lamp with a TRIAC can cause issues of flashing when off, as the slight leakage current through the snubber capacitors can be enough to charge the power supply in the lamp up to startup, which will make the lamp either flicker when off, or flash every few seconds."
But I could not find a solution to it being supplied in the post or across the forum that I could find.
So if you guys could help me with the same. I really appreciate it and thankful for your time.
Here is the modification I did from the schematic. I used the earth as the return for voltage resistor circuit for voltage sensing even though I knew the earth is such a bouncy return path.
Also I removed one of those 100nf capacitors in the 5V stability correction.
Also instead of the 360 ohm resistor and 470 setup changed it to the MOC3021 datasheet recommended 180 ohm and 2.4k combo resistance along with the 0.1uf X rated capacitor.
Looking forward for you instructions to rectify the issue.
It all worked fine until the load was resistive or inductive.
As soon as I connected a LED lamp to the circuit all problems started coming in to the circuit. When the TRIAC was off. The LED lamp started to flash every few seconds with each flash becoming
brighter than the one before it.
So when I read about it in eevblog forum. I found a post where Mr. SeanB had said " LED lamp with a TRIAC can cause issues of flashing when off, as the slight leakage current through the snubber capacitors can be enough to charge the power supply in the lamp up to startup, which will make the lamp either flicker when off, or flash every few seconds."
But I could not find a solution to it being supplied in the post or across the forum that I could find.
So if you guys could help me with the same. I really appreciate it and thankful for your time.
Here is the modification I did from the schematic. I used the earth as the return for voltage resistor circuit for voltage sensing even though I knew the earth is such a bouncy return path.
Also I removed one of those 100nf capacitors in the 5V stability correction.
Also instead of the 360 ohm resistor and 470 setup changed it to the MOC3021 datasheet recommended 180 ohm and 2.4k combo resistance along with the 0.1uf X rated capacitor.
Looking forward for you instructions to rectify the issue.