Sorry about that, even I am not purrphekt.
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LM317 2N3055 Variable Circuit Problems
- Thread starter heavyfletch2nd
- Start date
hevans1944
Hop - AC8NS
OMG! Here I am at 72 thinking, "Just a few more years, Hop, and you kin be purrphekt Just keep on keeping on." Now you come along and tell me, "Nope. Takes a little while longer." <sigh>Sorry about that, even I am not purrphekt.
If I were forty again, and knew then what I know now, I would change a few things. Things were exciting in the 1980s! I should have invested heavily in Intel stock... Things are still exciting today, too, but what should I do improve myself now that I am close to retirement age? A home-study course or two like @chopnhack has been pursuing sounds attractive... i would like to combine electronics with bio-technology and try to invent something no one will want to be without... maybe an implantable wrist watch with GPS tracker? Just visit your local tattoo parlor and have one written onto your wrist maybe?
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Hey, I live in Worcester. But I think my Worcester is about 3000 miles from your Worcester.
Bob
Keep at it Heavy , the water's fine but deep so keep swimming. It is really important to put some time in to learn the background and basics of what you are dealing with otherwise it becomes too difficult to grasp and apply to your next project. I feel like I come up against similar questions all the time that I should know the answer to... Try some good basic starting points - here is a link to some well liked books:
https://www.electronicspoint.com/threads/new-to-electronics.278915/#post-1693011
, the water's fine but deep so keep swimming. It is really important to put some time in to learn the background and basics of what you are dealing with otherwise it becomes too difficult to grasp and apply to your next project. I feel like I come up against similar questions all the time that I should know the answer to... Try some good basic starting points - here is a link to some well liked books:https://www.electronicspoint.com/threads/new-to-electronics.278915/#post-1693011
That's ok, I just didn't want our intrepid beginner to get confused... more confused... whatever.Sorry about that, even I am not purrphekt.
55 here. The body is going, but at least mind is still here to complain about it.
Lol lol you guys are funny Im sat in the shed chuckling after reading all those posts, im back at it I have it all working fine in the bread board no frying with new lm317 or arking in the adjust pot and a led to adjust on . But I jumped the gun again and copied it to my prototype board and guess what... I fried a lm317 and pot lol funny i did expect it this time tho. But on doing so I "think" I found why I'll explain before I fry more ,I replaced the fried 317 and found if I disconnect the capasitor from the pin 2 (vout) of lm317 to gnd it works "no frying going on now" I also added a led with 4700 resistor "yellow violet red" after like i think bluejets said for a load to the out pin it seems to work fine i can see the led adjusting in prototype board but I dont feel confidend to leave it running incase it fries the 317 again . I need to ask why should there be a cap between the pin 2 and ground?? Or am I being dumb and it shouldn't have been there, 10uf 25v it was rated. Thank you all you are ceeping me going i don't want to give up
you guys are funny Im sat in the shed chuckling after reading all those posts, im back at it I have it all working fine in the bread board no frying with new lm317 or arking in the adjust pot and a led to adjust on . But I jumped the gun again and copied it to my prototype board and guess what... I fried a lm317 and pot lol funny i did expect it this time tho. But on doing so I "think" I found why I'll explain before I fry more ,I replaced the fried 317 and found if I disconnect the capasitor from the pin 2 (vout) of lm317 to gnd it works "no frying going on now" I also added a led with 4700 resistor "yellow violet red" after like i think bluejets said for a load to the out pin it seems to work fine i can see the led adjusting in prototype board but I dont feel confidend to leave it running incase it fries the 317 again . I need to ask why should there be a cap between the pin 2 and ground?? Or am I being dumb and it shouldn't have been there, 10uf 25v it was rated. Thank you all you are ceeping me going i don't want to give up Hi bob if the cap is no good Can I use a different value cap? if so what range would you recomend . I have the cap straight off the 2 pin to gnd it is a + - cap, - being on gnd side, + on pin 2 just to confirm is this correct
hevans1944
Hop - AC8NS
IIRC, no capacitor is required on the output of the LM317, although a 10 μF from the ADJUST terminal to ground can be inserted to reduced ripple in the output. Try to keep this circuit as simple as possible until you get it right. Download and read the LM317 datasheet because it has application examples that might come in handy.
Right then bob it is ok so far "with transistors disconnected and no cap between pin 2 and gnd " ,it has been running for half hour or so with no hot bits lol I am stupidly happy lol "well so far" . Like dave said in a previous post one transistor at a time then 
ignor the red tapes they are the base wires fer transistors am i now good to one by one connect them?
ignor the red tapes they are the base wires fer transistors am i now good to one by one connect them?
Do you know how to do a basic check on transistors with your multimeter? Use the diode check range. Put the red lead on the base, and the black lead on the emitter. You should get a reading something like 0.5 or 0.6. Switch the black lead to the collector (case) and the reading should be similar. What you dont want to see is 0.0, which is a short, or an overrange indication, which is an open.
Thanks all I will look up all these radio shack things . Well it was working I hooked up one transistor to it and a car bulb it worked fine so I went ahead and hooked up another , the pot burst into flames as soon as I powered up , that is my first fire lol. No more 317's left 4 gone today 4 pots too ,I think im loosing faith in this particular circuit it must be wired right because it was working without transistors for about a hour, then it was working with one transistor lighting a tail light bulb for ten minutes , wired a second transistor pop ...all gone again:-(, it has been an experience all the same lol, well do I order more bits for another £8.00 lol yeh of course he will order more bits , I would love for one of you experienced guys to build this circuit just to make sure this circuit is valid or not, it makes me wander if it has even been built and tested , is it just a theory drawing or is it me , ok I admit I did make a few mistakes at the start by not understanding pin latout on the transistors ,but EVERY time I had it in the bread board it worked fine with no transistors , I made a few more mistakes along the way and learned a lot ,but this seems a easy circuit to put together using a lm317 to controll ×4 transistors I mean how hard can it be really!!!
Sorry about that, even I am not purrphekt.
Pop used to say it's ok to be known as a professional but never let them call you an expert.
ex .... out of
spurt...drip forced out of a tap under pressure
The only way I can see the pot getting cooked is if the 317 just fails short immediately for some reason. Otherwise there should only be about 5mA in that leg, no drama.
Are these 317s cheap fake parts or something?
Well modem head mabe you are right the 317's stay live full on if they dont split open , I put them in the bread board for a test after it all goes wrong " if they look ok by eye", they smoke pots and still give out nearly all the volts I put into them one or two were saying 8v , the transistors were new today along with the 317's , buying all these from ebay a seller called ( mc manager ) type into ebay lm317t you will find them , do anybody have a good link to buy these parts from I will try different brands of parts , I know I am a noob but l all I have learned this month from you guys and from the mistakes I have made at the start by not understanding a few basic pin layout's and the reed of a drawing witch I now know I should be able to controll 4 transistors with a lm317 just like I can control the brightness of a led or the brightness of a car bulb why cant I controll the transistors?? I would have thought a car bulb draws more amp/current than opening a gate on "well in this case just 2× transistors" I do not get it the amount of times I have checked this over and over there are no shorts all wires and connections are covered in shrink ,hmmmm . Cheers guys keep posting it is helping
Duke I just looked up the ammeter radio club in Worcester it is only up the road from me lol how good is that I cant believe that it is exactly where I grew up as a lad " no way" , thanks for that I'll go up see what they can teach/help me with on tuesday , nice one ;-);-)
The only reason I can think o for the 317s to die, causing smoke like that is:
1) AC or unfiltered DC input
2) output capacitor causing breakdown of the pass transistor's BE junction.
3) some subsequent failure causing the input to short to the ref pin.
I'm not certain this is a possible failure mode, but it explains why the circuit works when the output capacitor is removed.
1) AC or unfiltered DC input
2) output capacitor causing breakdown of the pass transistor's BE junction.
3) some subsequent failure causing the input to short to the ref pin.
I'm not certain this is a possible failure mode, but it explains why the circuit works when the output capacitor is removed.
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