Electronics > Beginners
Voltage Regulator Trouble (Solved)
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laus:
I circuit I build doesn't work as expected.  Full 13V was on sections where I'd expected 5V and 3.3V from the voltage regulators.

So I went back to he basic an tested a new LP2950-33LPRE3 volt regulator by itself.  Low and behold I didn't get the voltage regulator do its thing.  With and without the electrolytic capacitors the output voltage is just a little bit below the input voltage.  I tried it with 13V and 5V.  Measurements were taken with a multi meter.  Otherwise there was no load.

Specs: https://www.mouser.com/ProductDetail/texas-instruments/lp2950-33lpre3/?qs=iSMark9AYDUagDsOL8Eqdw%3d%3d&countrycode=US&currencycode=USD

What am I doing wrong here?
JS:
Is your device ok fpr 13.6V input? 10V drop? At the requested current?

Regulators need a minimum load to dp their thing, try 1k resistor from output to ground and test again, maybe try a second regulator in case they were fried, double check the pinout.

JS

Enviado desde mi LG-M250 mediante Tapatalk

laus:

--- Quote from: JS on June 07, 2018, 05:05:12 am ---Is your device ok fpr 13.6V input? 10V drop? At the requested current?

Regulators need a minimum load to dp their thing, try 1k resistor from output to ground and test again, maybe try a second regulator in case they were fried, double check the pinout.

JS

--- End quote ---

Thanks,

I added a 10k resistor from output to ground.  Not really any difference with that.

This is my second regulator I'm testing with and the pinout looks good to me.
JS:
So you are probably wiring it backwards, note that the datasheet shows the package from the bottom, your drawing looks backwards, try them again in the other direction, but they might be fried.

JS
laus:

--- Quote from: JS on June 07, 2018, 05:24:51 am ---So you are probably wiring it backwards, note that the datasheet shows the package from the bottom, your drawing looks backwards, try them again in the other direction, but they might be fried.

JS

--- End quote ---

Doh! Thank you.  Yes, I did wire them backwards.  |O 

  Claus
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