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Transformerless power supply

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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

So whats the problem ? Are you trying to get cheaper than that ?
 
A 500mA transformerless power supply is far too dangerous and is completely illegal in Australia.
I suggest we desist from helping this guy because it is obvious he doesn't know what he is doing and if he thinks he is going to put something lie this into production - he is a fool. I can get 50VA switch-mode power supplies from China for $2.50 with UL approval so why create a dangerous supply?
 
Trying to get a "CE" or "TUV" label for your product will be impossible to obtain in Europe - if you are heading for that market.

Getting low voltage at 500mA requires a huge capacitor rated 400VAC (X-class) which are not available on the market yet.

Even if there were such capacitors electric safety rules and tests would cost you $$$!.

Just keep it simple and use a suitable transformer for your project.

Boncuk
 
I have yet to find any sentence where the OP has mentioned going to public sales with his device.

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!

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.
 
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!

Not so bad on 110V mains, worse on 240V :D

Most supplies are switchmode, transformer less are very rare and only very low current ones.
 
I have yet to find any sentence where the OP has mentioned going to public sales with his device.
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.

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!
Yeah! Disassemble any GFCI. There is a "transformerless" power supply in every one. And there are lots of appropriate applications inside line operated devices.
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.

It seems like every time transformerless power supply threads arise we chase it around the same tree...with the OP determined that they have found the cheap, easy, and safe (in their mind) power supply solution.

Ken
 
I think a properly rated motor run capacitor will be bigger and cost more that a transformer for a comparably power supply.

That depends on what type of capacitors you are looking for. Most people are still not aware that much of the motor run types for the small fractional HP electric motors and HID lamp ballasts now use dry film type capacitors instead of the old metal can oil filled type.

I have a bunch of 250 - 500 VAC rated 5 - 22 uF motor run capacitors and lamp ballast capacitors that are in the same size ranges as common ice cube relays and medium sized axial lead electrolytic capacitors making them about 1/4 to 1/10th the physical volume of their old metal can type cousins despite having the same voltage, uF, and service life ratings.
 
I think I am seeing some good meat on the skeleton of some of the responses - I will look at switchmode- Thanks Derby Dude
 
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