Cheap solid-state power supplies - would these work?

[Spasticteapot]

I found these while looking for cheap SMPS power supplies for a class-D project.

Cheap power supply link

The output is 2KV AC at 10ma; this should give roughly 2.8Kv DC if put through a bridge rectifier. A voltage doubler would let this work very nicely for a small, cheap electrostatic solution.


Would these work?

[I_Forgot]

Yes, it would work but that kind of current can do some real damage if you touch the wrong place. I don't recommend it.

Keep looking...

I_F

[Spasticteapot]

Originally posted by I_Forgot
Yes, it would work but that kind of current can do some real damage if you touch the wrong place. I don't recommend it.

Keep looking...

I_F

What if I were to add a small isolation transformer or fuse? I'd like to try electrostatic speakers, and I'm poor.

[bear]

You can use this device, BUT.

You will need a large series resistor to reduce the available current.
Secondly, you will need good filtering at the output, since it runs at ~30kHz. You do not want 30kHz modulation on the diaphragm.

NOTE: THE CURRENT (@ 3kV) AVAILABLE IS DANGEROUS/DEADLY

That means extra parts.

The input is 12vdc @ 1 amp. A fair amount of power - so you need a fairly large "wall wart" to run it, or else you have to build yourself a power supply - more parts.

The open circuit is 3kv - you'll get 3kv, it's being run open circuit for all intents and purposes here.

It's probably equal or less in cost to take a typical small transformer with a secondary from 120vac or higher and build a diode/capacitive multiplier circuit to get the requisite HV that you need.

This is the traditional and typical time proven method.

One company takes a 120vac ---> 12vac transformer and then connects a second identical transformer backwards - it gets you back to 120vac, but ur isolated from the line AND you didn't have to buy an "expensive" transformer, just two cheapo transformers! Then they use a diode/cap multiplier circuit from there...

Given the low current being drawn you can likely get away with using something like a 120-->12 into a 6--->120 and get 240vac out to go to the multiplier and save a few sections of multiplier...

_-_-bear

[maudio]

I also agree that this module is way to powerful for this purpose. The additional cost for the heavy 12V supply and safety resistors/filtering will cancel out any benefits over the 'classic' approach.

Originally posted by bear

Given the low current being drawn you can likely get away with using something like a 120-->12 into a 6--->120 and get 240vac out to go to the multiplier and save a few sections of multiplier...

I suppose that should read: 120-->6 into a 6>240...
If you can find transformers with 2 seperate 120V primaries you can wire one for 120/6 and the second for 6/240.

Just don't feed more volts into a winding than it was rated for, to avoid core saturation.

[Capaciti]

Hi,

and the output is AC, but you need DC. Additional high voltage parts are required, which easily tripple the costs at the end.

Capaciti

[I_Forgot]

Originally posted by Spasticteapot

What if I were to add a small isolation transformer or fuse? I'd like to try electrostatic speakers, and I'm poor.

Being poor simply means you have more time on your hands than money, and that you need to be more resourceful. Keep looking and you will find a safe solution that is also low cost.

Check the on-line surplus dealers for HV power supplies. In the past I have found 5 kV at 1 mA adjustable supplies pulled from copy machines for $7. They are cheap because people figure they are useless with such low output current which is exactly what the ESL builder wants.

I just found this in the first place I looked in about 30 seconds:

http://www.herbach.com/Merchant2/mer...egory_Code=PWS
2000 VDC, 5500 VDC both well under 1 mA, $7.95. Brand new, available in large quantities in case you decide to go into production. What more could you want?

here's an adjustable one for a few dollars more, and it has a 24V output, too:
http://www.herbach.com/Merchant2/mer...egory_Code=PWS
The output current is a little high, and you'll need to put a load resistor on this one, but it is adjustable over the range of 3kV-7kV, right about where you want to be able to adjust it.

I_F

[Spasticteapot]

Originally posted by I_Forgot



http://www.herbach.com/Merchant2/mer...egory_Code=PWS
2000 VDC, 5500 VDC both well under 1 mA, $7.95. Brand new, available in large quantities in case you decide to go into production. What more could you want?

here's an adjustable one for a few dollars more, and it has a 24V output, too:
http://www.herbach.com/Merchant2/mer...egory_Code=PWS
The output current is a little high, and you'll need to put a load resistor on this one, but it is adjustable over the range of 3kV-7kV, right about where you want to be able to adjust it.

I_F

Awesome!

Now, to find some perforated metal.