How can I run a AA battery operated appliance on house (120 volt) current?

Question

I've got a small battery operated shop appliance that runs off 2 AA batteries. It goes through batteries quickly, and since I don't really need it to be portable, I'd like to figure out what kind of transformer I could use to run the utility off of house current (120 volts in US North America).

Understand that I'd have to do some soldering to connect the transformer leads, just don't have a clear understanding of what transformer specifications I should be looking for. Appreciate any help anyone can offer, and thanks in advance.

Answer 1

well you need a transform ac to dc that is easy to find at you local electronic store now the amp well i,m just guessing that maybe 700ma to 1100ma will work the best and you might get one that has a volt selector

Answer 2

Have you looked to see if your appliance has a socket to run it from a mains adapter, many do and the adapters come with a range of plugs to fit anything.

I agree with gvstach to be careful about what you buy though. Adapters are very cheap but this reflects in the quality. Don't make the mistake of selecting one too much above the rating you need because they rely on having the correct load to drop the voltage to the correct level. If the appliance has electronics you may consider something better than a cheap unregulated anyway. The rating should be on your appliance.

Consider the cost of your appliance when you look at cheap adapters. You always have the option of rechargeable batteries.

Answer 3

transformer just changes AC voltages from one to another. You need 3 volts DC.

Go to Radio Shack or the equivalent and get one of those small plug in supplies. Find one that supplies 3 volts at perhaps 1 amp. Get a good one, some of they are not very good. You need to find out or guess how much current your appliance uses. If you can't find out from the documentation, find out how long a new set of batteries last if it is used continuously and calculate from that. But I'm guessing 1 amp is enough.

If you are lucky there will be a small jack on the appliance where you can plug in the plug from the supply. If not you will have to strip the wires and solder. Make sure you get the polarity correct. Use a voltmeter.

Answer 4

Look on the item. It should have the voltage and current rating stamped on it. If not, look under specifications in the owner's manual.

Go to a department store or electronics store and buy a UL listed replacement power supply with the same DC voltage and equal or only slightly higher current (amp) rating. Hook positive to positive, and negative to negative.

Now for the stuff they don't tell you at the department store. No all replacement power supplies will work for 2 reasons.

One is filtering. Cheaply made DC replacement power supplies (wall warts) do not have very good filtering inside which may introduce 60 or 120Hz interference. Also, the voltage rating of DC supplies are rated in RMS. They charge to 1/Sine 45 or 1.414 when unloaded: a 10VDC supply will likely put out 14.14 volts when unloaded.

The bottom line is this: don't do this to something you value a lot if it's not designed for it. You probably shouldn't do it anyway. IF you are determined to, leave it unplugged when not attended.