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Calculating power supply (australia)


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Hey everyone, 


Just starting out and have a few questions about calculating the power supply, not wanting to set the house on fire! This is probably a basic question, but trust you all to help, me out. When looking at the Voltage of my lights, should I be focusing on the 'output' DC voltage which is lower and hovers around 10V-40V or the 'input/rated' AC voltage which is around 110V-250V range. If it helps, im located in australia :) hoping someone can assist with the basics before i go ahead and start planning for this year! Thanks

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Actually you need to be concerned about both the input and output. The input 110v-250v must match the wall recetacle that you will be plugging the power suplly in to. The output must match your lights so if the power supply output is 10v-40v and you are using 12v lights then you are good. However, if you are using 5v lights on that output then it's not good as the 5v lights don't fall into the 10v-40v range.

Now after saying all that, most power supplies have a switch on the side so you can set them for the input voltage so make sure you set that for your location. As for the out put, make sure you adjust the output voltage to match your lights before attaching them. Example: connecting 12v lights to a power supply putting out 40v is not good and lights go POOF. Before connecting lights use a meter and adjust output voltage for the lights requirement.

Edited by Mr. P
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You need to read the Input label carefully. 120/240 implies a switch or jumper change is needed. 110-250 implies auto range.  The other thing is your mains voltage stays INSIDE the designed range.

The Output voltage spec you cite makes me cringe. That could mean UNREGULATED or it could mean adjustable. Who does the adjusting??  You need a quality, calibrated  DVM if you DIY.

What is the regulation rules (some supplies need a minimum load to  stay within regulation: 10% is a common value for 12V. 5% for 5V) Light shows go from almost 0 A (a tiny fraction powers the board) to full load in a fraction of a second. 12.6V  is my set point no load (but ALSO check with 1/2 rated load that it stays below 13.2. Some supplies inverse vary under load)

Last: is Duty Cycle. How long are you going to be at Rated Output (W or A)?  Running at 100% rated output for very much will be harder on the internal input capacitors. Your 50Hz is harder on them than our 60Hz.


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