Took apart my lamp because it was shutting off after 1 minute and found a capacitor in line on the hot leg. Why?
1 Like
Is it an LED lamp? Maybe it is part of a capacitive dropper circuit though Ive not seen one attached directly to the mains lead before…
1 Like
It’s a regular lamp I got from ikea. Is it supposed to make the light bulb blink? I don’t see how.
It’s a fuse, not a capacitor. Just there to stop overcurrent from surges killing the LEDs.
1 Like
If it’s a fuse why would the lamp shut off after a minute? A burned out fuse should not allow any current. Also this is a brand new lamp and has a single screw in socket for regular light bulbs
It’s a resettable fuse. They trip when they reach a certain temperature, and become conductive again once they’re cooled down.
Either the fuse is faulty, or the lamp’s running out of spec for some reason. They’re designed to run at room temp, so it could be insulated too much(?).
2 Likes
@Zavar is right about it being a “resettable fuse” (PTC thermistor).
The light likely flickers because the PTC gets hot, goes open circuit, and then when it cools down it closes the circuit, and then the cycle repeats.
According to the datasheet, it should trip at 0.27A (32W @120v), at a frequency of 1.5 seconds (if I’m understanding the datasheet correctly). If you’re using a tungsten filament bulb (ex. halogen, incandescent), instead of LED, that may be why it “blinks”.
3 Likes
Like others have said, that is not a capacitor, that is a PTC thermistor.
Without it, you risk the lamp overheating and all the 
that comes from that.
1 Like
thank you. didnt know such a thing existed. yes i am using a regular tungsten bulb. I just removed it and replaced the plastic lamp bulb socket with a regular ceramic one.
This topic was automatically closed 273 days after the last reply. New replies are no longer allowed.