Do PWM controllers/dimmers cause EMI noise? Alternatives?

[pekka8]

I would like to dim 12V fans and led lights. Easiest solution seems to be PWM dimmer switch. I have read, and it makes sense, that PWM causes electric pollution - EMI.
Is this true, and if so, is there an analog alternative for dimming led lights? For fans it's easy to make diy resistors.

 

[profesor79]

PWM regulation is used in many devices, so at first it will be better to know what kind of instalation you have.
In fact as long as there is no audio devices connecetd (that can reproduce this in the speakers) or sensitive medical devices, then I will not even think about EMI impact in this case.

 

[pekka8]

PWM regulation is used in many devices, so at first it will be better to know what kind of instalation you have.
In fact as long as there is no audio devices connecetd (that can reproduce this in the speakers) or sensitive medical devices, then I will not even think about EMI impact in this case.

(not getting any alerts from forum)

I'm looking this from health perspective, both electrical and light flicker.

 

[SunDave]

Hi pekka8,
In all but the best LED lights, they use PWM to run normally. There are very few modern bulbs that don't, and most have quite a bit of flicker from the PWM. And I have only looked into the 120v stuff.

It's unfortunate the tech went this way, but it's what sells I guess.

 

[profesor79]

(not getting any alerts from forum)

I'm looking this from health perspective, both electrical and light flicker.

Light flicker can be very disturbing for ppl with autism spectrum (or other stuff), as this is something that draws their attention and overloads their sensors - and here I am talking about very small filckering that most of us need to focus on the bulb to see it...

 

[SunDave]

Light flicker can be very disturbing for ppl with autism spectrum (or other stuff), as this is something that draws their attention and overloads their sensors - and here I am talking about very small filckering that most of us need to focus on the bulb to see it...

I guess I see it a lot without autism. The led taillights on cars, if you move your head to look around, all trail pretty bad. I tend to see it mostly in peripheral vision. I have not went to LED in my own house because I would rather be happy and healthy than save a few kW. So I think it is worth discussion.

Any thoughts about using a good fluorescent or even halogen bulb? Just use the efficient stuff for lighting you are not around a lot. 12v will be a lot harder to find than AC/120 bulbs. If you end up using an inverter, there are some good nearly no flicker LED bulbs. This is a good video on light bulbs if you have 15 mins to watch it.

 

[HarryN]

The little dial pwm controllers that people often buy on amazon cause all kinds of issues in vans.

I don't think this is so much about the concept as the implementation of these cheap units.

LEDs are technically best fed using constant current controllers, but you can come close to this using a constant voltage and an in line resistor.

I have become more of a fan of LED light strips with built in resistors and fed using a constant voltage supply over time.

In the US, LED supply and super bright leds come to mind as suppliers, with LED supply being the more durable ones. Not sure about in Europe.

If the PWM frequency is high enough, then most people cannot see the flicker, but there is a frequency in the 100 - 300 hz range that can really mess people up who are sensitive to it.

 

[pekka8]

I can see or sense the flicker on my Samsung phone screen, for example. Installed a software dimmer app to solve that. Fortunately there are led lights that have voltage dimming (or is that the constant current controller?).