The Shop > Electronics & IC Programing
What am i doing wrong?
shipto:
--- Quote from: shipto on April 05, 2015, 05:40:09 AM ---
The lm338k is a 5 amp power regulator which is supplying the 24v line and this is working fine
--- End quote ---
:lol: :lol: :lol: :bang: :bang: :bang: :bang: :lol: :lol: :lol:
The resisters must have been the only voltage regulation that was going on here because the lm338k's where fake.
I have solved the problem I was having another way but took another one of these to make another power supply for something else and while checking on the net for the diagram I found so I opened up a few of mine and see pic
rowbare:
What did the guy in the video expect to find in there? A pony? There is no way that one could tell using a gram kitchen scale whether or not a chip is real.
There isn't a whole lot in any IC. See the little square "nose" under the eyes made by the leads in the third picture? That, in all likelyhood is the circuit.
I am not saying that your chip was not counterfeit but that test is worthless.
bob
shipto:
I know that part is the chip but that is approx 2.5mm square and the wires going to it where 0.06mm thick I would guess that its a chip thats meant to carry a few milliamps just so that you get the correct voltage. The lm338k is a 5 amp regulator I would say the wire would need to be a bit thicker than 0.06mm I am sure someone with more knowledge would be able to work out what thickness would be required to carry 32v at 5 amps but judging by car fuses I would guess around 0.8mm maybe?
There are other clues too the lettering is easy erased by just rubbing with fingers, I believe the origional manufacturers use a more robust printing process also it is not quite square and none of the measurements on the spec sheet are correct all are close but I suspect the manufacturer would be pretty precise about these details.
All of which is no help to me I have solved the problem another way and ordered more chips from rs components now, the cheaper lm338t rather than the lm338k. I am just thankful that I didnt pay the price the proper lm338k's are worth.
John Swift:
more info on fake semiconductors
http://www.hq.nasa.gov/office/codeq/trismac/apr08/day2/hughitt_NASA_HQ.pdf
http://www.cti-us.com/pdf/CCAP-101InspectExamplesA6.pdf
on an IC data sheet I have
it noted the IC package can be dissolved by - Chlorine-based solvents: Trichloroethylene, Trichloroethane, etc.
Aromatic hydrogen compounds: Benzene, Toluene, Xylene, etc.
Keton and Acetone group solvents
I may have to try it some time :D
John
PS
for a bit of fun , if you was interested in photos of the silicon dies http://micro.magnet.fsu.edu/creatures/pages/enterprise.html
http://micro.magnet.fsu.edu/creatures/index.html
Baczlwding:
--- Quote from: shipto on April 05, 2015, 05:40:09 AM ---Working on a project that requires a dual voltage power supply 24v and 5v my electronics skills are limited to following other peoples circuits and this one is me combining 2 seperate circuits.
Please excuse the crude drawing but I have included it to show the way I am attempting to accomplish this.
The lm338k is a 5 amp power regulator which is supplying the 24v line and this is working fine however the lm317t which is intended to take that 24v down to 5v is the problem no matter what i do I cant seem to get it to work I am getting 24v on the 5v line.
I have searched and cant seem to find the answer but I am sure it should work and can only assume I am missing something.
Thanks for any help
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