Where can I get a transformer to convert 120VAC to 12VDC. A minimum of 10A of DC current is required. I don't need any type of housing or cords/wires. Open/exposed terminals on a transformer I can place inside a box is fine.
If you need 12VDC, you need a power supply with caps and circuitry. Google a 12vdc power supply.
http://www.powersupplydirect.com/ProductList.aspx?CategoryID=2998 Dnk...
[This message has been edited by Dnkldorf (edited 12-12-2005).]
Thanks Dnkldorf.
That is what I am looking for but the cost is much higher than I expected. Isn't it normally more "expensive" to convert from 12VDC to 120VAC than vise-versa? I'm sure the unit you showed me is of much higher quality than the "cheapy" 12VDC inverters at the big chain stores. However, for the same price, I can get one of those to convert DC to AC (same VA). Are there also "cheapy" versions of AC to DC converters? This is not for a job so top quality is not a necessity.
$85 for a 120 Watts Switching-mode DC power supply is not too much.
This one
http://www.jameco.com/webapp/wcs/st...amp;catalogId=10001&productId=540728 is a linear power supply which cost $70, and is not for DIN mounting.
Joe.-
Here's a 150W switcher from MPJA 12V, 12.5A <$50.00
I buy alot of stuff from these folks and always get their email specials.
Joe
http://www.mpja.com/category/Power_...UPPLY_1_DC_POWER _SUPPLY_16020_PS.asp If you want to do your own rectifier, filter, & regulator, here is the 24VCT, 10A TX that they sell for $17.99 http://www.mpja.com/category/Transformers/24V_CT_(12-0-12)10A_TRANSFORMER_7846_TR.asp
[This message has been edited by JoeTestingEngr (edited 12-12-2005).]
[This message has been edited by JoeTestingEngr (edited 12-12-2005).]
George is on the right track. 10a out of a PC supply isn't that hard to find, probably <$10 on Ebay.
Where can I get a transformer to convert 120VAC to 12VDC.
Just so some readers are not confused, you can't use a transformer to change AC to DC.
Don
A PC power supply, like most switching supplies, will not work without a minimum load on the output. For a PC supply, that load would have to be on the 5V output, not the 12V in order for the supply to start up properly.
$85 seems completely reasonable for an industrial DIN rail power supply like that.
NJ, maybe some old PC supplies need a 5vdc load to start (particularly the old IBM PC/AT supply) but I have a buttload of them that don't. I have been using an assortment of PC supplies for bench supplies. They start fine without a load. Some will shut down when the load changed significantly, some don't
Try Google searching for a company called Moose. They were great for cheap power supplies. Also if you have an ADI store in your area, go there and they have just what you are looking for in stock.
What do you actually want to run on the 12V DC? That will determine just how well the output needs to be regulated, what sort of ripple voltage would be acceptable, and so on.
Without delving into the entire project, I am looking to power a car stereo (and possibly a small DC motor).
Being a former RF engineer and avid amateur radio operator, there lots of way to get to the point where you want. Since you mentioned car radios, and dc motors, how about a car battery and float charger?
Any ham fest or ham web site has tons of 12 (actually 13.6) power supplies up to 50-amps for dirt cheap.
triple: Without delving into the entire project, I am looking to power a car stereo (and possibly a small DC motor).
Maybe I'm being old fashioned, but it was usually preferable to use linear supplies, as opposed to switchers, in audio applications. Ripple voltages and possible radiated noise from the switcher can have nasty effects in your audio path. (Like high freq. buzz). And you are probably really wanting a 13.5 VDC for your car stereo to get the most out of your final. It is probably wise to take your motor drive off of your input filter network via a separate path so that your amplifier supply and motor supply are isolated.
Joe
1) A battery is out of the question since weight is an issue.
2) I've changed my plan and a 12vdc motor will no longer be used. Thus, the car radio will be the only load.
Still hard to beat a $5 PC supply for simplicity in the development stage. If you want to refine it to some special purpose $50 supply when you get past the prototype go for it.
Odd sounding device... weight is an issue in a device that uses household voltage?
Why am I picturing a walkman personal radio with a power cord?
Using a computer power supply to power 12V devices is common, especially among computer efficianados with high-currenet 12V devices. Be aware of two things:
ATX power supplies will NOT work out-of-the-box. They are designed to be switched from the motherboard, so you will have to manually modify the motherboard cable with some simple circuitry to "trick" the PSU into believing the motherboard has instructed to turn it on. Older AT power supplies do not have this feature and always supply power when they're turned on.
Also note that most power supplies are designed to provide power to a computer as a whole, with typical balanced power on 5V, 12V, and other supplied voltages; if you leave all the lines unloaded and load the 12V side down, some will not work at all and others may give varying results (eg, 14V or 10V output, something like that.) It's hit or miss; DIY hobbysts don't sweat soldering a resistor on a 5V wire to balance the load and if you're just jerry-rigging an old car radio, this could be the way to go, but I wouldn't do this for something critical.
Considering how many of these things are sitting "free" on junk piles of old computers, it's very tempting, isn't it?
[This message has been edited by SteveFehr (edited 12-15-2005).]
[This message has been edited by SteveFehr (edited 12-15-2005).]
ATX supply, you ground the green wire from pin 14 to start it. AT supplies are either on with the switch or (IBM Aptiva and similar) you tie the black and white wire together on the 3 wire connector. A paper clip in the connector holes works.
Dell ATX supplies have a different pin out but the green wire is still "start".
These things have internal overload protection that shuts them down so it is hard to blow one up. Some will shut down if the load changes suddenly.
Triple I understand the car battery size thing, try thinking more like a motocycle or alarm battery. Something small, it doesn't have to be a car battery.
What ever you do, consider you really want 13,6 volt dc since you are going to use it for a car radio. A 12 volt PC supply could leave you short a few watts of audio, like 25% short. E^2/R
[This message has been edited by dereckbc (edited 12-16-2005).]
If you decide to use an ATX power supply here is a link that may be useful for you.
It is the pinout of an ATX supply.
http://xtronics.com/reference/atx_pinout.htm