Can anyone out there help me with a problem. I have an electronic (TRIAC) dimmer that is controlling an electronic lighting transformer. The dimmer works by switching the supply on and off and this causes the sinewave to be chopped up. This is stressing the electronic transformer, causing it to buzz.
Do you know how I could smooth the output waveform of the dimmer to reduce the buzzing?

Many thanks, Peter

well, you could try an inductor in series with the transformer. the rate the voltage drops from high to low is e^-t/(tao). where tao=L/R where R is the resistance and L is the inductance.

I think your problem is that the voltage tries to drop very quickly, and the inductance of the transformer tries to oppose it, and thus has a fairly large force on it at about 60hz. if you can take the edge off the voltage transitions before they get to the transformer, it may stop/reduce the buzz.

I am only an electrical engineering student, who specializes more in digital, so take my advise with a grain of salt. but if you have time to mess around with it, you could try it.

although, I would just try a different type of switch. there is probably something out there better than a triac.

Here is an FAQ (http://www.jantecneon.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=Jantec&Category_Code=FAQ) that includes questions about the dimming of neon signs. The triac controller may not be the right kind of controller for the sign. It may cause the transformer to catch fire. Jantec builds the controller into the transformer. A separate dimmer is probably the wrong type.

Can anyone out there help me with a problem. I have an electronic (TRIAC) dimmer that is controlling an electronic lighting transformer. The dimmer works by switching the supply on and off and this causes the sinewave to be chopped up. This is stressing the electronic transformer, causing it to buzz.
Do you know how I could smooth the output waveform of the dimmer to reduce the buzzing?

Many thanks, Peter


Hi Peter,

I am new here too, I think I have a good answer for you.
Whenever you switch a pure sine wave at any frequency it causes harmonic current to flow in the opposite direction of conventional current flow. The harmonic current is at a higher frequency than the fundamental current and this is causing the vibrations in your transformer windings.

I would have to say that it sounds like this is a small single phase application for controlling a few lights at most. Line inductors are expensive and difficult to properly install to code. Also it isn't practical at this level of power.

The solution is fairly low tech. Make sure that you are using the proper type of dimmer. There are different types of lighting ballasts which require a unique type of dimmer. Also keep in mind some lights are not designed to be dimmed.

I hope I helped.

yes, the consensus seems to be that you need a different dimmer.
try something like this:
http://gallery.bcentral.com/GID5110980P4874094-Neon-Power-Supplies/Plug-in-Neon-Dimmer-Electronic.aspx
maybe not a plug-in one, but you get the idea. find a dimmer for a transformer, so you attenuate the signal, and don't chop it.

What I have is a 12V track with two 50W halogen lamps connected by a 105VA electronic transformer. (not a wire wound type) This is fed from an 60W to 700W x10 dimmer. The transformer claims to be compatible with "Most dimmers" I have tryed small inductors in series and capacitors across the dimmer output. None of these work. Do you think it is worth trying a Lutron transformer as they seem to manage to work with the Grafik eye OK?

What I have is a 12V track with two 50W halogen lamps connected by a 105VA electronic transformer. (not a wire wound type) This is fed from an 60W to 700W x10 dimmer. The transformer claims to be compatible with "Most dimmers" I have tryed small inductors in series and capacitors across the dimmer output. None of these work. Do you think it is worth trying a Lutron transformer as they seem to manage to work with the Grafik eye OK?

Do you live in europe?
What is your input voltage to the dimmer?
What type of ballast do you have?
What type of dimmer do you have?