With the wide availability and low cost of LED strip lights, I've started embracing them for lighting on and under the layout. For my first project, I've run a 16ft strip under my layout for illumination for working under the table. Initially I was just using a 12V DC wall wart but given I have transformers already powering trains, lights, and accessories and I wanted to use my AIU to switch the lights on, I derived a simple circuit to wire it in to my accessories using a full bridge rectifier.
After hooking it up, it illuminated as expected, however I noticed quite a bit of flicker in the LEDs. My suspicion is it is because of a squared/chopped sine wave being produced by the Lionel CW-80 transformer. I hooked up my LED lights/rectifier to an old Lionel Type 1053, and sure enough the flicker is gone. I don't really want to switch to using the 1053 if I can help it as I like the integrated overload/breaker protection in the CW-80 (yes, I know I can install an in-line breaker or fuse, but I'd prefer to just use the integrated design of the CW-80). Rather, I'd like to try and address the flicker/chopped sine wave in my circuit design (if only for self-education in basic circuit design)
I installed a 220uF 16V capacitor across the DC leads on the "back end" of the bridge rectifier to try and eliminate the flicker, however that has not seemed to help. I believe my next step would be to install an inductor or two in serial after the bridge rectifier and before the capacitor:
A few questions/observations for the forum members here:
- Is my inference about the chopped sine wave correct with the CW-80 vs 1053 and would that chopped sine wave result in the flicker I'm seeing?
- I've noticed the bridge rectifier gets quite warm - nearly too warm to touch/handle. A bit of quick research online says this is somewhat normal, but can anyone on this forum confirm?
- I've noticed my capacitor is also getting warm, which has me a bit more concerned - the fact that it's getting warm tells me it's doing work, perhaps it's charging/discharging as the polarity shifts due to the chopped sine wave?
- Is my inference about inductors being my next step correct to help eliminate the LED flicker?
- What size/attributes/quantity of inductors should I install? I assume they need to be installed in serial after the rectifier and before the capacitor