Calling electricians: How to make a MH ballast dimmable
- Thread starter haninja
- Start date
Or it uses something similar to a TLx94 (TL494, TL594, etc) If so the pot would be used on pin 6 in conjunction with pin 5 of the IC to change the duty cycle thus varying the output voltage of the ballast. I'm going to assume that the ballast we are talking about is an electronic ballast. If not, then the only 2 ways to make the ballast dimmable is to A. vary its input voltage. The transformers output voltage is directly proportional to its input voltage. So lower input voltage then output voltage will be lower. B. Vary the output voltage with a potentiometer. Is the idea feasible? Maybe, especially for a electronic ballast. They should be basic switching power supplies. I am not familiar with ballasts as of yet but I will open one up some day.
After I move. :doh: Just my 2 cents
Jason (Ace of Spades) would be correct in that a TRIAC (Triode for AC) or SCR's (silicon controlled rectifier) for higher power applications would be the most likely, and the most efficient, method of controlling current to a lamp.
http://en.wikipedia.org/wiki/TRIAC">http://en.wikipedia.org/wiki/TRIAC</a>
[IMG]http://en.wikipedia.org/wiki/Silicon-controlled_rectifier">http://en.wikipedia.org/wiki/Silicon-controlled_rectifier</a>
What has to happen is that the lamp voltage must be maintained while reducing the current. This is not an easy feat to accomplish, as the resistance of the lamp changes as the heat disippated changes. Kind of like trying to shoot something on the fly.
The TRIAC's/SCR's do this by switching at very high frequencies, sort of like switching a light on and off at the wall switch rapidly (thousands of times per second). You end up producing less overall light output.
The circuitry required for doing this reliably is not simple, and requires formal electronics design training. The engineer's that design these type of devices often specialize in SCR type controls. -JMHO
http://en.wikipedia.org/wiki/TRIAC">http://en.wikipedia.org/wiki/TRIAC</a>
[IMG]http://en.wikipedia.org/wiki/Silicon-controlled_rectifier">http://en.wikipedia.org/wiki/Silicon-controlled_rectifier</a>
What has to happen is that the lamp voltage must be maintained while reducing the current. This is not an easy feat to accomplish, as the resistance of the lamp changes as the heat disippated changes. Kind of like trying to shoot something on the fly.
The TRIAC's/SCR's do this by switching at very high frequencies, sort of like switching a light on and off at the wall switch rapidly (thousands of times per second). You end up producing less overall light output.
The circuitry required for doing this reliably is not simple, and requires formal electronics design training. The engineer's that design these type of devices often specialize in SCR type controls. -JMHO
Similar threads
