oldkardon04
Pioneer Enthusiast
and not the toys either, i'm looking for a transformer that puts out 15 amps at 12 volts, anyone know where i can find one for a decent price?
transformers
- Thread starter oldkardon04
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Chad Hauris
Super Member
The output of a battery charger is more than 12 volts...it is unregulated and unfiltered...don't use it to power a 12 volt electronic device.
WhiskeyRebel
Registered thread killer
Also it may only be half-wave rectified, which would make the ripple beyound hell to filter out. But if you used only the transformer and added rectification and filtering to it, could you build a power supply out of one?
oldkardon04
Pioneer Enthusiast
ok, new problem, i found a transformer, but trying to figure it out.
my buddy said there is no pos and neg, it doesn't matter, this is the transformer. http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=120-205
my buddy said there is no pos and neg, it doesn't matter, this is the transformer. http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=120-205
oldkardon04
Pioneer Enthusiast
just to test a car stereo, eventually i'm gonna use it for other 12v projects.tubino said:
jpchleapas
Active Member
oldkardon04 said:
Ummm. All you have to do to test a 12v car stereo is wire it to a charged 12v battery. That is how they test them in the auto boneyards I have been to. Don't spend crazy money when you can just wire it to your battery. John C.
Now if I can find a pair of vintage power transformers for my 300b set project life would be good.
oldkardon04
Pioneer Enthusiast
12 bux is crazy money? its only a 12 volt 5 amp transformer, i already have it, i'm trying to figure out how to wire it so i don't burn my house.jpchleapas said:
clifselina
Active Member
Wait!!!!!
A transformer will put out a nice AC signal, in some ratio of the primary and the secondary. If you apply 120 to the primary and you get 12 from the secondary, then the ratio is 10:1. Is you supply power to the secondary, then 1200V will come out of the other side. Not a very good thing.
Besides, a transformer only puts out AC, which will kill whatever you are trying to test. Do you have a voltmeter?
A transformer will put out a nice AC signal, in some ratio of the primary and the secondary. If you apply 120 to the primary and you get 12 from the secondary, then the ratio is 10:1. Is you supply power to the secondary, then 1200V will come out of the other side. Not a very good thing.
Besides, a transformer only puts out AC, which will kill whatever you are trying to test. Do you have a voltmeter?
oldkardon04
Pioneer Enthusiast
one out in the garage, but i guess i wasted 12 bux, because i went ahead and bout a 12v 14 amp bench tester, that way its all plug and play.clifselina said:
how would i be able to use this transformer to make dc power?
is there anything else i would have to get to make it act like the bench tester i'm getting?
tubino
A guy with too many tubes
oldkardon04 said:
You have to rectify the AC, which is usually done with a bridge rectifier, a single component made up of 4 diodes.
Then you have the filter the rectified AC, usually with a capacitor that links + to -. The cap acts as both spring and reservoir, sort of, to absorb the ripple peaks and fill in the valleys, 120 times per second.
The filter stages are sometimes described as CRC, to mean a capacitor, then a series resistor, then another capacitor. If you like iron you can use a choke (L) instead of a resistor, and get more filtering that way. (I built a 10v power supply with chokes to power the filaments of directly-heated triodes, because I had a lot of the chokes, and it works great.)
Your bench tester may include voltage regulation, and meters.
Chad Hauris
Super Member
In our shop we use a regulated 12 volt power supply from Radio shack to test car audio equipment.
Would recommend searching google for 12 volt power supply circuits, here is some info:
http://www.techlib.com/electronics/regulators.html
It should be regulated, as just rectifying and filtering the output of a 12 volt AC transformer will be higher than 12 volts DC and the voltage will vary according to the load current.
Would recommend searching google for 12 volt power supply circuits, here is some info:
http://www.techlib.com/electronics/regulators.html
It should be regulated, as just rectifying and filtering the output of a 12 volt AC transformer will be higher than 12 volts DC and the voltage will vary according to the load current.
oldkardon04
Pioneer Enthusiast
ok so i searched for a rectifier, and found this at parts express http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=1N5349
it didn't tell me anything about it, and i couldn't find much on google about that exact part
if you could, take a moment to look around http://www.partsexpress.com and point out what i need to use this 12v 5 amp transformer, and turn its output power into dc volts, i have a multimeter so i can test to see whats coming out of it before i actually plug something into it, but i don't want to order one part at a time.
it didn't tell me anything about it, and i couldn't find much on google about that exact part
if you could, take a moment to look around http://www.partsexpress.com and point out what i need to use this 12v 5 amp transformer, and turn its output power into dc volts, i have a multimeter so i can test to see whats coming out of it before i actually plug something into it, but i don't want to order one part at a time.
Chad Hauris
Super Member
no...that diode you had found is not what you want...it is a zener diode, used in voltage regulating circuits for providing a reference voltage.
here is a rectifier I would suggest:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=050-060
you hook the two 12 V AC output leads from the transformer to the AC terminals, then you have your DC output from the other two, + and -.
As I said...you will need to construct a regulator circuit too, please research this some more. Don't just hook up the rectifier output to an electronic device without a filtering and regulator circuit.
here is a rectifier I would suggest:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=050-060
you hook the two 12 V AC output leads from the transformer to the AC terminals, then you have your DC output from the other two, + and -.
As I said...you will need to construct a regulator circuit too, please research this some more. Don't just hook up the rectifier output to an electronic device without a filtering and regulator circuit.
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oldkardon04
Pioneer Enthusiast
thank you and will do, but any further help would be much appreciated, i think my cuzins friend might be able to help me further though, if not i won't hesitate to ask any questions, hopefully i get answers :scratch2:Chad Hauris said:
oldkardon04
Pioneer Enthusiast
one question that i left out, i see that is designed for 400 volt though, or is that just the max amout of volts it will accept?
oldkardon04
Pioneer Enthusiast
would i be able to use a kit like this in some way shape or form, i see its only able to either handle or put out 1 amp, but would i be able to use the parts in it for reference to build a regulator, or do i have to start from scratch?
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=320-216
or would this work fine, i couldn't find much information on it, but maybe one of you guys knows the model number and have had experience with it.
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=NTE933
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=320-216
or would this work fine, i couldn't find much information on it, but maybe one of you guys knows the model number and have had experience with it.
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=NTE933
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