hello, I made a simple triac phase-angle control that blinks a string of incandescent fairy lights (20W total) in various patterns as a kind of hobby project.

It works, but my question is about RFI. This article here recommends fitting a 100uH choke and 100n capacitor to suppress RFI (fig.4.) What kind of choke do I need? The local supplier only seems to have small-signal chokes (the color-coded ones) that go up to 20mA or so (my understanding is the limiting factor is current.) That isn't it, is it? Can I wind one myself around one of those ferrite cylinders from an old cable?

That aside, how much of a problem is RFI really, specifically in a little circuit like mine? Quantitatively, is the bigger problem the EM radiation or mains power getting harmonics? So far other appliances don't seem to mind, neither does my FM radio.

Thanks

edit: s/wire/wind
edit: sorry, 0.17A (which is 170mA, not ~20mA)

 

Are you dimming the lights or just blinking them?

 

Are you dimming the lights or just blinking them?

it's various effects, on-off blinking, stairstep (0%,30%,75%..), sawtooth (ramp), sine... the control is on a half-cycle (10ms, continental Europe) basis

 

Any choke from 47 to 110uH will do rated at your maximum current draw, with a 100nF capacitor 630VAC rated, 20W isn't a lot of current @230V that's 100mA,,.

Pulsing won't cause much interference dimming will be noteced more on inductive loads on AM radio.