110 VAC to 20VDC Question

I'd say so.

Here's a nice 0 to 45V 0.5A HP power supply going for $10.

You don't say what your power requirements are, but there's a 20V, 6A unit on ebay right now, and the bidding as of 7:51 AM PST Wednesday is at $149.89:

Just shop around. You can buy something for much much cheaper than it would end up costing you if you're not experienced at building stuff and designing stuff and specifying components, albeit, if you only want an educational exercise, you should shop around surplus places and ham fests and that sort of thing. If you can get a surplus transformer then building a supply with some diodes and filter caps and a regulator could be a reasonable beginner's exercise, depending no how much work you want to do. :-)

Good Luck! Rich

A question. I have 110VAC coming in, and need to (cheaply) be able to provide 20VDC out. What is the quickest and cheapest method? A transformer? Are there other means that might be a bit more expensive?

Thank you!

Thanks Phil, but can you point me in the right direction? What are some other means that might cost as much or slightly more?

Terry

Sorry, I suppose that would help. I have a coil that will heat up some fluid. I am trying to keep this as inexepensive as possible, all the parts and pieces totaling no more that $7 or $8 dollars. The transformer, while it sounds like it is the cheapest, might also be the most cumbersome and heavy, that is why I was looking for alternatives.

Does this help?

Thanks

you also need a rectifier if you want DC, but it is not clear that is needed for a heater application. If you only need heat, consider a large wattage resistor and eliminate the transformer entirely.

Why does it have to be DC?. Heaters are equally happy with AC, and this reduces the parts needed, to just the transformer. Basically, if isolation is required, a transformer will have to be involved (it is the only economic way of providing isolation of this sort). Smaller transformers can be used, by increasing the operating frequency, bu this adds the complexity of converting the incoming power to DC, then chopping this at a higher frequency. If DC is required, then rectification will have to be added, and if the voltage needs to be smooth/stable, smoothing, and possibly regulation. Normally if you look at things like low voltage halogen lighting, and fish tank heaters, a simple transformer is used. Assuming there is some reasonable current involved, except in very large production, you will not get any other solution, down to the desired 'price point'. However the key 'missing data', is how many amps are involved...

Best Wishes

Not much. I can't see why you need DC though.

How much power do you need man ?

Graham

"Terry Dennis" schreef in bericht news:l57xf.35188$ snipped-for-privacy@tornado.rdc-kc.rr.com...

Not enough. What's the power rating of that coil or what's its resistance? Why do you ask for DC, is the inductance of the coil really that high? Do you need insulation between 110Vac and the coil?

petrus bitbyter

"Terry Dennis"

Boy, that was as easy one ;-) .

.......... Phil

"Terry Dennis"

Explain what your application is and give us a few numbers eliminate the mysteries.

....... Phil

"Terry Dennis"

How many amps would that be ??

BTW

Your price limit exclude low weight solutions.

....... Phil