Hi Guys, I followed the power supply buildin tutorial, and it lights the light but the voltage reg gets very hot and smokes, i then put the thermistor in and it has to cut the power off every time i turn it on. Have ordered new voltage reg, but why is this happening? photos are on the link below:
http://www.ksd-design.co.uk/photos/photos.html
The circuit is correct i;m sure…
Do you have both of the electrolytic capacitors oriented so that their negative terminal is connected to ground? I can’t quite tell from your pictures.
The regulator could also get hot if the input voltage is too high.
Linear regulators work by converting the excess voltage into heat.
So, a reg that converts 30v in 5v will heat a lot more then one that converts 8v in 5v
I can’t read the chip, but it looks a lot sleeker than any of the 7805s I have in my stash. A lot of other 3-pin regulators have different pinouts. If you got the wrong regulator, you might have it hooked up wrong. If it’s not a 7805, It’s a good idea to look up the pinout from the datasheet for the exact part number you have.
Why do you have a small value capacitor hooked up in series with your unregulated voltage?
-Bill
Its a thermistor i think your looking at, so that if i did make an error it would cut the current before anything blew up
If the voltage regulator is getting hot and the resettable fuse opens right away, you have a wiring mistake or the chip is defective. Clicking on your link I can only see the first photo, schematic, and parts list. The schematic calls for an ASM1117-x and the first photo shows a TS1086CP-x. Which are you using? I can’t find a datasheet for the ASM1117. The TS1086CP-x datasheet indicates that pin 1 is ground, pin 2 (heat sink tab) is output, and pin 3 is input (pin 1 is the leftmost pin as shown on your photo). Check over the wiring of the regulator and confirm that it is wired properly.