Dimming Controller (Circuit)

[Chinny]

i know that i would be able to buy a "Dimmer Controller", but, first they cost a small fortune and second i would like to build it myself !

it would be used to control 2 T5 fluorescent lamps in my aquarium, it is possible to dimm the ballast (it has a 10v output).

i would like to put the PCB in a housing that could, in turn, be plugged into a 230v socket, a cable would be connected from inside of the housing to the 10v connection on the ballast.

when anybody could help me, i would be very gratefull !

(it would be no problem to get hold of the parts and PCB here in Germany)

it could be automatic or automatic / manual

 

[Chinny]

maybe the wrong part of the forum ?,
i hope that somebody can help me out.

 

[bmcculla]

In general Florecent lamps don't like to be dimmed. They need a certain voltage to run correctly. If you relpaced then with incandecent lamps a dimmer would be fairly easy - you can buy a dimmer circuit in a hardware store for a couple bucks.

 

[Nigel Goodwin]

Yes, fluorescent lamps are very difficult to dim, you can't do it in the normal simple way that you can for incandescent lamps.

If you really want to do it, I would suggest buying a commercial fluorescent dimmer - they are expensive, but probably cheaper than you could build one - it's not a trivial project!.

 

[Oznog]

Even commercial dimmers for flourescent tubes may not be a great idea. The tubes tend to blacken near the electrodes when run at any substantial power reduction, and the commerical one may be better at preventing the effects but I doubt they can prevent it.

You could have several tubes and change how many you switch on. Also, one guy asked on the microcontroller forum here about using LEDs in a way which dimmed over the month with the lunar cycle which is really cool. LEDs are perfectly dimmable, even better than incandescents. I don't know if the differences in color spectrum will have negative effects on plant growth, though. Perhaps you could use the flourescents in the daytime and dimmable LEDs at night? You'd also probably want either a lot of LEDs or really big ones from Luxeon.