Electronics > Electronics

Did I burn my voltage regulator?

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ribs:
Hi - I just "finished" soldering my $50 robot, for the most part.  Earlier I accidentally put in the voltage regulator in backwards, and decided to desolder it, pull it out, and put it in again.  Unlike the other few other places where I was using desoldering braid to great effect, it took a lot of frustrating fiddling to get the solder off the 3 pins (I assume because of the heat sink built into the chip).  When I went to pull it out, the heat sink was very hot.  Not hotter than boiling - I touched a damp sponge to it and it didn't hiss - but quite hot.

I hear those ICs are very easy to mess up if you heat it up too much with the iron.  What are the chances I fried something in there?

The reason I am concerned is while doing my connectivity test I noticed that I have non-infinite resistance across any two of the voltage regulator pins (e.g. ground to input, input to output, ground to output).  The multimeter moves around when I measure resistance, but it kind of homes in around 240ohm if I measure resistance across Ground and Input.  Then it occurred to me that I have no idea what resistance it should read anyways, so I have no way of telling if it's busted or not.

I have not yet attached any servos or anything - I've essentially finished step 3B and am doing the connectivity test of step 3C.


Thanks,

Ken

ed1380:
mine has gotten so hot so many times and it still works

I have a 150watt gun and I didn't fry it, burned my fingers and it still works

frank26080115:
I measured a 7805
all non infinite
Try measuring the output voltage instead
the one and only time my regulator got hot, the output dropped from 5 volts to 1.4 volts, but that was a LDO regulator

Admin:
Put it in to a breadboard, wire it up, and measure the output voltage with a multimeter.


--- Quote ---the one and only time my regulator got hot, the output dropped from 5 volts to 1.4 volts, but that was a LDO regulator
--- End quote ---
Some regulators have whats called a 'thermal shutdown' which basically stops the flow of electricity when it overheats.


--- Quote ---I was using desoldering braid to great effect, it took a lot of frustrating fiddling to get the solder off the 3 pins (I assume because of the heat sink built into the chip).
--- End quote ---
The last time I used a desoldering braid was back when I was a noob . . . but I remember it being totally useless . . . get a solder sucker (~$10), they are amazing!

ed1380:

--- Quote ---I was using desoldering braid to great effect, it took a lot of frustrating fiddling to get the solder off the 3 pins (I assume because of the heat sink built into the chip).

--- End quote ---
150watt gun FTW

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