Noise from LED lights

[stolzy]

I have a Starcom/iPod/intercom/GPS/iPhone/radio system which works OK.

I have recently put on a pair of these lights and I get a high-pitched whining noise.

Any idea how to get rid of it?

 

[VFRman]

Did a google and found this:

Since LEDs are constant-current devices, the most efficient way to drive them is with PWM (pulse width modulation), allowing their brightness to be independent of supply voltage. The crude method is a series resistor, but you lose a lot of power to heat. There are good and bad ways to design a PWM circuit, and the bad ones are massive noise generators... big sharp square waves turning a load on and off, worsened by the inductive antenna of the wires between them.

You can improve things somewhat with strategically placed ferrites and capacitors to eat some of the noise impressed on the power leads

 

[Boon]

small decoupling caps between +ve and -ve will take spikes to ground

if you want to be really creative work out the frequency of the interference and build an LCR trap

 

[Hman]

small decoupling caps between +ve and -ve will take spikes to ground

if you want to be really creative work out the frequency of the interference and build an LCR trap

tell us more?????????????? what size caps, ive got a few .68uf left over from a cmoy amp ive built.

Hman

 

[Boon]

For a wide range cap only spike killer try a 22nF and 100 pF in parallel


or put 5nH choke and around 20 -30 M/ohm Resister in series with each cap and place both in parallel


kinda standard 10-200 Mhz noise killer circuit

 

[Hman]

For a wide range cap only spike killer try a 22nF and 100 pF in parallel


or put 5nH choke and around 20 -30 M/ohm Resister in series with each cap and place both in parallel


kinda standard 10-200 Mhz noise killer circuit

thanks Boon, i'm a numpty when it comes to electronics. i've had some sucsess with building off plan but i have no idea with design. anyways since the fitment of a hid i get interferace through our intercom, like stolzy. ive tryd all sorts of permitations of wireing it all up with no sucsess. with your knoweledge you should do a " electronics sticky for bikes".

Hman