Why dimmers are different for normal and LED bulbs when both are connected to normal power?

Question

The title 😀

I would understand it for LED strips and so on, but if both bulbs are made for 230V (or whatever in US), why do they need different dimmers? Is there a difference in some dim range or something?

Thanks.

In: 14

Answer 1

LEDs are ultra low power so some of the cheats for dimming an incandescent don’t work

Dimmers for LEDs need to consume less power themselves. Normally they leak some power through the light to keep themselves functional even when its off. On an incandescent this works fine because a few milliwatts won’t heat the filament and make it glow. On a 3 watt LED bulb this leakage power can charge the bulb and make it flash occasionally or glow dimly

The lower current of the LED is also a problem to drive. Most dimmers these days use a triac to chop up the line voltage and only send some of it to the bulb. The triac sits off, voltage hits the right point in the line cycle, triac turns on allowing current to flow, current drops to 0 at the end of the cycle and turns the triac off, then it sits and waits for a bit

Well LED bulbs use low enough current that they won’t hold some triacs on so instead of turning on halfway through the cycle and staying on until the end, the triac will turn on, stay on for a bit, then turn off well before the end of the cycle and cause cause all sorts of flickering in the bulb as it comes on and off.

Controlling a toaster is easy. Controlling electronics is finicky