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LM317 2N3055 Variable Circuit Problems

ModemHead

Dec 2, 2010
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Glad to hear about having some more success without part destruction. Sorry I wasn't around last night, off to a college football game (the funny American kind, not soccer.)

The upgraded bridge rectifier and panel meter sound like good additions. In the meantime keep monitoring with the multimeters so things don't get overloaded.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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If you need more than 10A or have a voltage differential x current greater than 70, (or you want better regulation) then you'll need multiple transistors and a different circuit.
 

heavyfletch2nd

Jun 27, 2016
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I know bluejets and the cap makes it flicker before it goes out right lol Im too young for knitting;) . modemhead no probs hope it was good, your football is like our what we call rugby i know lol , i see becham came to u,s to show you how to play "soccer" didn't he lol:rolleyes: , we call It foot ball too or "footy" for short ;) , I have a ameter for this psu too but it came with no shunt and no specs appart from 5v 200ua " micro amps" I think, is it a must to have a shunt all the emitter wires are pretty fat?. and steve i have five more lm317t,s and six transistor's a few caps resistors various sizes how different would the cuit be or could i stablize this one i have built and put protection diods in and mabe variable current once I have a better rectifier , it really didnt mind doing 4.5A off one transistor , I was supprised how good one 2n3055 was , it was only the rectifier that would have popped if one more amp and not on a sink , I'll try catch "yoall" tomorrow lol cus u know im in a funny place 400am ... nice one :);):cool:
 

heavyfletch2nd

Jun 27, 2016
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Finally got the new 50a rectifier but I dont understand it . Wich pin goes where could someone help me with that20160908_172105.jpg

i have connected the ac to the ac side of this and it just gets hot ?
 

BobK

Jan 5, 2010
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It should not get hot at all when there is no load. Try testing it with the diode test range on your multimeter.

With the positive lead to the + pin, each AC pin should read something like 0.6V
Same with the negative lead to the - pin.

Bob
 

heavyfletch2nd

Jun 27, 2016
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I have already tested it bob its no good ,0.1 all over . The place I bought it from said the ac in was where the ac marking is and the terminal behind it and the dc is the + marking and the terminal behind that . I have looked at a data sheet for this but it does not say anything about the ac and dc pins .
 

BobK

Jan 5, 2010
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There are 4 pins, right? Two marked AC, one marked + and one marked -, right?

Bob
 

Bluejets

Oct 5, 2014
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Top drawing shows what you have in block form.
Lower drawing shows what is inside the "block".
Hope those needles are still handy .......................:)
 

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  • Bridge Rect.jpg
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heavyfletch2nd

Jun 27, 2016
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Thanks LOL:rolleyes: I thought the same when I smoked the rectifier " I may end up knitting after all " , I mailed the shop I bought it from he said he meant opposite corner apologiseed and sending me another for free lol.. rolls of wool not rolls of wire :p. Thanks for the pics :)
 

heavyfletch2nd

Jun 27, 2016
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There are 4 pins, right? Two marked AC, one marked + and one marked -, right?

Bob
No bob only one pin was marked ac and one + the other two were blank ,witch is why I asked the shop what was what before attaching wires, the guy at the shop said the side wich had the ac on it was ac and the spade behind it , he apologiseed and sending another for free .
 

Bluejets

Oct 5, 2014
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mmm...always pays to check....preferrably before you apply the juice
 

BobK

Jan 5, 2010
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Okay, that explains it. I am surprised only 2 of the pins were marked.

Bob
 

heavyfletch2nd

Jun 27, 2016
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Hi bob.I can finally finish this project when the new one arrives . I would like to know if I can fit a ammeter without a shunt ..the emitters wires are fat wires.
 

BobK

Jan 5, 2010
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Depends on what you mean by an ammeter. If the meter is spec'ed to read the range of current you need, you simply put it in series with the output. If you are talking about an analog meter that reads 0-1mA, however, a shunt is needed.

Also, there can be a problem if the ammeter is powered from the power supply itself. This might constrain one of the inputs to be ground, which is not so good if you want to ground your power supply with the house wiring.

Bob
 

heavyfletch2nd

Jun 27, 2016
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Hi all i been buisy rebuilding this psu, I thought I would update you with a few pics "almost there" 20160828_233455.jpg
20160913_173946.jpg 20160913_183046.jpg


i need to wire up the ammeter now . I have two wires one black and one white i think i need a shunt i have connected these two wires to the negative about 5 inches appart from eachother but not getting the readings the same as the dmm any advice on this would be helpfull . Cheers guys
 

heavyfletch2nd

Jun 27, 2016
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Job done . Thanks to those who posted the help . Special thanks to steve and modemhead putting in a lot of help :)20160916_005106.jpg20160916_005040.jpg
 

BobK

Jan 5, 2010
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Not finished yet, you need knobs!

Congratulations. You are now absolved from the requirement to take up knitting.

Bob
 

heavyfletch2nd

Jun 27, 2016
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Yes I need nobs bob lol :D , only one pot is wired up to volt adjust until later on , i would like to add a amp adjust but i dont think it is possible " or is it possible " hi modemhead how you doing not seen u here for a while lol :)
 
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