Brevor
Member
I have made a transformer power supply already supplying 600ma for $2.50 already - so $7 is not of any use
So whats the problem ? Are you trying to get cheaper than that ?
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I have made a transformer power supply already supplying 600ma for $2.50 already - so $7 is not of any use
As far as transformerless power supplies go in the USA they are everywhere. Odds are if you live in the US you have more than one in use right now and don't even know it!
Post #8. When you start talking "cost per unit" I will assume that the OP is not looking for one power supply for their personal use.I have yet to find any sentence where the OP has mentioned going to public sales with his device.
Yeah! Disassemble any GFCI. There is a "transformerless" power supply in every one. And there are lots of appropriate applications inside line operated devices.As far as transformerless power supplies go in the USA they are everywhere. Odds are if you live in the US you have more than one in use right now and don't even know it!
I think a properly rated motor run capacitor will be bigger and cost more that a transformer for a comparably power supply.500 ma at 5 VDC may be pushing the normal view of what a transformerless power supply can run at but it is by no means undoable or any less unsafe than any other transformerless design, just a little larger. If the circuits are all encased in plastic and non of the control circuits requires any external connections other than through buttons or switches there is no reason it cant be run off a transformerless power supply system.
As far as finding AC line rated capacitors in the correct size I would suggest looking at motor run or small power factor correction type capacitors. They are designed specifically for working directly across AC line power and work quite well in larger transformerless power supply applications. Also being mass produced they are rather cheap as well.
I think a properly rated motor run capacitor will be bigger and cost more that a transformer for a comparably power supply.