hid’s, can you dim them

Hey guys, I'm pretty new to electronics and I'm really just wondering if it's been done out of pure curiosity. Is it possible to dim HID ballasts by any means that would provide a smooth and wide range of brightness for your lights? I was considering getting HID's, I like the color of the 4300k/5000k lights, but I don't like how bright they can be.

You would need to lower the ballast ark set voltage to even attemp to dim them as lowering the frequency would lead to flicker, even then it would be limited because of the resistence of the bulb gap which has to be adjusted (Shorter)to go dimmer with lower voltage. So basicly no not really in that sense.

Actually dimming for LEDs & fluoros and halogens etc is usually done by NOT lowering their voltage (typically because they'll extinguish at lower voltages or dimming is not proportional to voltage etc). Hence PWM circuits are used - ie, high frequency with varying on-off duty cycle (ie, current chopping). The frequencies used are much higher than our detectable flicker frequency. Whether that can be done with the ballasts or circuits concerned varies with the circuit.

That won't typically work HID's for the fact of it's a controlled ark not excited gas like Florucents. They are simular if the fact that they need high voltage from ballast to start and use a gas that's ionizes but drop back to around 24vac constant current once started (ie simular like a spark plug firing at 240Hz= 240p/s)but with lower volatage due to the ioniized gas. Ther are newer types of HID's that have a glow mode and then can transition to a full arc output (HID lamps (HPS and MH lamps). Minimum voltage to sustain the ark at minimum set constant current + the lenght of the ark will determine the minimum light output.

So you are saying that reduced voltage can dim HIDs?

It's not that simple the new style of HID's have 2 stages glow and ark but the voltage is much much higher than the standard HID's. New style HID lamps need an appropriate voltage across the electrodes to initiate and mantain glow discharge. Furthermore the ballast should provide sufficient current at glow discharge voltage(appr. 90V for HPS and 180V for MH) forcing the glow-to-arc transition. Therefore, the ballast should provide increased open circuit voltage (>600V) for MH(Type I, 2+1 electrodes) lamps and high voltage pulses (2000 - 3000V, 1µs) for MH (Type II, 2 electrodes) and HPS(2 electrodes) lamps.