dear chris,
thank you for replying
i really appreciate it
the reason in want a 220 V source is when i was overseas, i purchased
some electronics that use 220V.
because we have 110V coming out of the wall, i need something that will
allow me to still use the device that uses 220V
so, what is the best way to do this
O.K. 120VAC in, 220VAC out.
Simple. Use something called an autotransformer. It's a one-winding
transformer with no secondary, with a tap at the halfway point. If you
apply 110VAC between the center tap and the bottom, the autotransformer
will induce a higher voltage at the output, like this (view in fixed
font or M$ Notepad):
|
| o----------.
| | )|
|220VAC )|
|Output.-------'|
| | | )|
| | | )|
| o--)--o----'
| | |
| | |
| | |
| o--' |
| 110VAC |
| Input |
| | |
| o-----'
|
(created by AACircuit v1.28.6 beta 04/19/05
www.tech-chat.de)
These devices are commercially available in sizes from 50VA (1/8 amp at
220VAC) to 1KVA and up (over 4 amps at 220VAC). The commercial units
have built-in fuse protection. You should pick the size that will work
for you.
Remember that your line frequency will not change -- if your 120VAC
source is 60Hz, your output will be 60Hz, too. If you've got something
with a motor in it, and your original 220VAC frequency was 50Hz, you
should check to see if it will be OK before you plug it in.
Most line voltage is closer to 117 or 120VAC, so your output will be
more like 234 to 240VAC. That shouldn't make any difference.
If you're looking for a good 110-to-220VAC commercial autotransformer
that's not too expensive, you could do worse than Jameco P/N 85008PS,
which will give you 300 watts of 240VAC power (a little more than an
amp, suitable for most electronics) for only $27.95. It's got built-in
plugs so you don't have to worry about wiring anything. Of course, the
iron in the transformer will make shipping a little more expensive.
http://www.jameco.com/
Good luck
Chris