AC to DC convertor

Those of us who have caught the bluetooth bug are using simple AC to Regulated 5VDC modules  to power the sound boards. Cost is about $1.50 for parts. 

you can search ebay for buck boards that do that for you for a few dollars. Just put in the facts of what you're after.... Volts, AC to DC, etc.

You might also put a full bridge rectifier inline and just use a DC to DC board.

Thank you all for your help

Ken M

I have been using these from the bay and they work pretty good for converting track power to light my leds

Step-down Power Supply Converter Module AC 2.5V-27V/DC 3V-40V to 1.5V to 27V

Thank You

These little AC to DC converters are great and inexpensive.  I have a city scene with lots of sidewalk lamp posts which were too bright at 14 VAC, so I dimmed them to suit my liking using one of the variable converters.  I keep spares on-hand as easy fix solutions for my next emergent problems.

Question?

How many LEDs can be run off of one of these AC to DC converters?

Thanks.

Depending on your power supply, lots.  The cheap (<$2) buck/boost converters I use on my layout are rated at 3 amps.  I would not load them past about 80%, so let's say 2.4 amps.  The LEDs I use draw between 5 and 20 milliamps (ma) apiece.  Let's use a number on the high end, 20 ma, for the sake of discussion.  2.4 / .020 = 120.  You can do the math for different LEDs and for converters that have different output ratings.  The converters are so inexpensive that you might want to use several to spread out the load and remove a single point of failure.

LED lighting has truly revolutionized layout lighting.  My prior layout was all incandescent, and I had to add a small cooling fan to my vintage KW transformer to keep it from cycling the breaker during long operating sessions.  Now that transformer doesn't even break a sweat.  My single Woodland Scenics wall wart at 1000 ma has enough capacity to power all 8 of my JustPlug structures plus all of my street lighting with capacity to spare.

laz1957 posted:

Question?

How many LEDs can be run off of one of these AC to DC converters?

Thanks.

Retinpa beat me to it !

Lots.  Each led might be 20Ma.  Here’s a couple pics of the specs, as we aren’t allowed direct links to ebay items here.  The third photo are my connections to all the lights in the layout photo.  The diagram looks confusing, but start upper right at xfrmr acv out follow yellow arrows through step down module to buss then out to lights and a second dcv step down module that I wanted 4.5vdc out.  Power all the leds on layout with these.  Course not the trains or xmas tree

FWIW, running the 3A converters at 1.5 amps things get pretty warm, so I'd set the estimate at 50-75 20ma LED's as a practical limitation.  The regulator IC they use is rated at 3 amps, but that assumes a pretty good heatsink.  Also, to draw more power from these would likely require heatsinking the bridge rectifier and increasing the filter capacitor value.

Thanks for that input GRJ.  I was hoping that if my numbers were overly optimistic, someone with more practical experience with these converters would jump in.

Just use a Buck Converter as they don't get hot.  Analog voltage regulators get hot and waste power.

Casey, we are talking about a buck converter.  They do indeed get hot, just not nearly as hot as a linear regulator handling the same current.

Thanks GUYZ for the explanation of these converters.  Now I need to purchase some.