My kitchen lights (incandescent) are hooked up to a dimmer. Recently, whenever I try any dimmer setting except the full-power setting, they randomly flicker off and on rapidly. I take it I probably need a new dimmer. Besides that fact, is there any danger in leaving them setup this way for now? As long as I leave the dimmer turned up all the way, it’s kinda like having a push-button switch for my lights.
P.S. What’s actually causing this within the dimmer? It’s one of those big-old-round-knob types.
EDIT: On further investigation, the dimmer has now decided to allow 0 light upon any setting except for the highest.
I’d wager to guess there’s a break in the rheostat somewhere, the lights where flickering as a small spark jumped across the break. Full power probably bypasses the rheostat. That’s my WAG anyways.
Rheostats haven’t been used in dimmers for at least 40 years. I don’t think they were used in home lighting, ever. The home dimmers are SCR/Triac circuits.
The main danger in leaving them set that way is that the bulb will burn out quickly when they are flickering like that. But the dimmer is failing; replace it with a new one (probable cost of less than $5).
Could someone explain TRIAC circuits to me? I have the general idea of electrical stuff, but need to know more about the specifics. A rheostat I can understand, although I know it is outdated. But stuff with electronics in it? Not my thing.
Thank you sir/madam. The Wikipedia definition seems to me to suggest that it in some way resembles the function of a transistor - I mean, I seem to recall that they use small currents to make proportional changes in larger currents.
But see, I’m trying to recall stuff I learned in hi skool 17 years ago. So explanations have to be aimed at the “guy who heard of this kinda stuff years ago and ain’t got a clue” level. And when I Googled it, I had to plough through tech info that is way beyond my understanding.
Rheostats are used in the timing circuit but not as the current limiting device. Regard - rheostat R2 draws a small current which charges capacitor C1. Changing the charge rate alters the firing rate of Q3, the TRIAC. Load current flows through the TRIAC and the coil, but not through the rheostat.
To get away with using a simple resistor as a power control device, you’d have to use a resistor capable of dissipating as much power as the load itself dissipates. 5 and 10 watt resistors are as big as your thumb. A 150 or 200 watt resistor with adjustable taps is this big, and I can’t imagine anyone sticking that inside a light switch box.
