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Electronpusher0 · 9th Sep 2019, 10:33 am

All this talk of fakes has got me worried.
About a month ago I purchased 5 off LM317 kits from e-bay to keep in stock but I have not tried them yet.
So this morning I built one.
The pcb is very good and has the recommended capacitors and protection diodes.
I admit I tested it from a bench power supply connected across the output of the bridge rectifier so that I could current limit it in case the smoke got out.
I connected a metal clad resistor of 82 ohms as a load.
It works fine!
The voltage varies from 1.24 volts to about 2v below the supply. I tested it up to 25V input.
I attach photos, the LM317 may be fake, in any case I have a supply of quality 317s so will use them when I use the kits in anger.

Peter

9th Sep 2019, 10:33 am	#38
Electronpusher0 Nonode Join Date: Jun 2016 Location: Bognor Regis, West Sussex, UK. Posts: 2,302	Re: Defective/ fake LM317T All this talk of fakes has got me worried. About a month ago I purchased 5 off LM317 kits from e-bay to keep in stock but I have not tried them yet. So this morning I built one. The pcb is very good and has the recommended capacitors and protection diodes. I admit I tested it from a bench power supply connected across the output of the bridge rectifier so that I could current limit it in case the smoke got out. I connected a metal clad resistor of 82 ohms as a load. It works fine! The voltage varies from 1.24 volts to about 2v below the supply. I tested it up to 25V input. I attach photos, the LM317 may be fake, in any case I have a supply of quality 317s so will use them when I use the kits in anger. Peter Attached Thumbnails