Need Some Electrical Expertice

[FCIN]

Sorry to ask silly questions but here goes anyway. I need an inexpensive 120v AC to 12-14v DC transformer to power an Aristo-Craft Radio Control Throttle. I saw one at the local Radio Shack that said on the box that it was 120v AC to 14v DC 5000mA. Am I correct that 5000mA = 5 Amps? Just want to be sure that the output is 1 Amp or higher before I plunk down my $28 for this transformer.

Thanks!

[nachoman]

Milli = 1/1000, so you are correct. 5000 mA = 5 amps. That transformer will work fine - but bear in mind the output will be 14 V AC, and you will need a bridge rectifier to convert to DC. The rectifier is made of diodes, and will reduce the voltage by about a volt and a half. Your output DC voltage will be about 12.5 volts. Also, depending on the application, you may need filtered DC, in which case you need a few large capacitors to filter the output current.

[FCIN]

Milli = 1/1000, so you are correct. 5000 mA = 5 amps. That transformer will work fine - but bear in mind the output will be 14 V AC

Glad to hear that my electrical knowledge wasn't too far off. The transformer I mentioned converts the AC to DC output so the bridge rectifier isn't an issue.
Thanks!

[Gary S]

Ed, if you don't mind, how much does that cost?

[FCIN]

Ed, if you don't mind, how much does that cost?

Gary;

Haven't been back to Radio Shack to pick up the transformer, but seems like the price was about $28.00. Comes with a couple of adapter plugs, but of course I'll simply solder spade clips on the wire so I can attach it to the throttle unit.

I've looked on the Radio Shack web site and can't find it listed, but they had several different transformers for converting 120V AC to DC or lower AC voltages.

[Gary S]

If it was $28, that is a great price for a 5 amp DC supply.

[nachoman]

If it was $28, that is a great price for a 5 amp DC supply.

Depends on where you buy it from. A dedicated model railroad power supply will run you much more. If you are crafty, you can find a more generic power supply or salvage one from another appliance. A 12v auto battery charger could work, as could power supplies used for electronics hobbyists or computers. I have one that I hauled out of a dumpster, and all I needed to do was move one wire over and replace a fuse to make a 12V AC and DC supply.

[FCIN]

Gary;

Will try and remember to let you know what the transformer cost and how it worked out when I get back out to pick one up.

[ezdays]

Bear in mind that this power supply is most likely unregulated. That is, the output voltage can vary, dependent on the load. The higher the load (more current drain), the lower the voltage will be. If you need a more precise voltage output, then it's best to look for a regulated supply rather than this one.

[Steamtrains]

I've used "salvaged" computer power supplies for the "jump" throttles for the Digitrax Zephyr. They require some minor modifications (adding a $2.00 sand resistor and removing all the extra wires you don't need), and you're good to go. Can't beat nearly-free for a price..!!

[nachoman]

Bear in mind that this power supply is most likely unregulated. That is, the output voltage can vary, dependent on the load. The higher the load (more current drain), the lower the voltage will be. If you need a more precise voltage output, then it's best to look for a regulated supply rather than this one.

I wonder about that. I tore into a small wall wart a few weeks ago and was surprised to learn it was regulated. It should probably say in the description on the packaging, right?

[FCIN]

Picked up a 120V AC to 12v DC 1.5 Amp transformer at Radio Shack this morning and it works just great! Must have been half asleep the other day, as I did not see one rated at 5 amps (5000mA) like I thought. But this one fills the bill for what I needed it for. Cost was $25. It's an Enercell - Radio Shack part no. 273-358 (Custom Manufactured in China no less)

[Gary S]

That's what I was wondering about! A 5 amp DC supply is alot of electrical oomph! I suspected that the 5000 mA rating may have been caused by sleepiness!

[FCIN]

I suspected that the 5000 mA rating may have been caused by sleepiness!

Well I got a notice from the eye doc today saying it was time to get my eyes checked again - so maybe I'd better go huh?

[P5se Camelback]

While we're all here and talking about this sort of thing ... I have ...

" 'Tripp Lite' Model PR-10b Powerverter 10 AMP Precision Regulated DC Power Supply."
Input: 117V AC 60 Hz Fuse Protected
Output: 13.8 V DC 10 AMP Fully Regulated Low Ripple

It is a "Left-over" from my 1/12th scale R/C Touring Car Racing days of 8 to 10 years ago. I used it to power an elaborate, expensive Tekin set-up to charge my brace of NiCad batteries that were (are) all linked together with my custom solder-up quick change wiring harnesses in 2x3 "pacs" and used to power my wicked little low-slung, all-wheel drive, carbon fibre chassis, fully-adjustable fully-tunable four-wheel independent suspension (multiple spring rates, four oil weights in multiple gate choice shock absorbers, electric-powered screaming 55mph Honda-bodied race car. It was fun! hock: Now they run gas-powered machines with gearboxes -- too much for me!

So now I'm wondering if there is a future for this twenty pound lump under the Lehigh Susquehanna & Western? :? :?:

Whaddya think? :?: