Why do the LED lights on my layout flicker? – Reader Q&A

If the lights on your layout flicker, follow this advice that I gave to Paul who contacted me over the weekend.  The answer was simple but of

Over the weekend I got an email from a visitor to MRE who was having problems with the LED lights he’d fitted into an engine shed on the layout.

The lights were coming on but flickered.

While an interesting effect it wasn’t the look Paul required and was disconcerting distraction on the Ratio model he’d spent ages making..

After a few emails back and forth the problem became apparent.

He’d connected the LEDs to the 16V AC accessory terminals on his Gaugemaster controller.

The problem, of course, is that LEDs typically need DC — direct current. Hence using the AC terminals was producing the flicker he’d observed. Actually, it’s likely that with prolonged use the AC supply will probably destroy the LEDs!

I suggested he use the DC accessory terminals that are available on the Model D controller being used and this solved his problem. (The AC terminals should be left to point motors, etc)

If you have this problem but don’t have DC output terminals an alternative power source will be needed (along with resistors). A standard adaptor for other household electrics can be used — just look for 1AMP 12V DC output.
Update: I should point out that there are LEDs that can now work with AC although these aren’t the usual ones found in model railway shops but they are available if you look around: search for AC LEDs.

> A final, personal, note: I spend a huge amount of time testing, photographing, writing and researching techniques for these articles and pay for all the running costs of MRE out of my own pocket. If you found this article useful you can support me by making a donation on my fund-raising page. Thanks and happy modelling, Andy.


Founder of ModelRailwayEngineer, Andy Leaning

Andy is a lifelong modeler, writer, and founder of modelrailwayengineer.com. He has been building model railways, dioramas, and miniatures for over 20 years. His passion for model making and railways began when he was a child, building his first layout at the age of seven.
Andy’s particular passion is making scenery and structures in 4mm scale, which he sells commercially. He is particularly interested in modelling the railways of South West England during the late Victorian/early Edwardian era, although he also enjoys making sci-fi and fantasy figures and dioramas. His website has won several awards, and he is a member of MERG (Model Railway Electronics Group) and the 009 Society.
When not making models, Andy lives in Surrey with his wife and teenage son. Other interests include history, science fiction, photography, and programming. Read more about Andy.

Afflliate disclosure:The links on this page may take you to carefully selected businesses, such as Hornby, Amazon, eBay and Scale Model Scenery, where you can purchase the product under affiliate programmes. This means I receive a small commission on any orders placed although the price you pay does not change. You can read my full affiliate policy here. I also sell my my own ready to use, pre-made and painted buildings and terrain features. browse the range.
One comment
  1. I fitted front and rear lights to an updated Triang Dock Shunter. The white LEDs on the rear flicker when running forwards, the cause, back emf from motor. Haven’t done it yet but an extra diode in the chain should quench it.

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