Temperature sensor LM35DZ

[Frit]

Am I missing something trying to use a LM35DZ temperature sensor by simply putting 12v across it and measuring the voltage on the middle leg? When I try I get 0 volts with ground where I expect 2-3v but 8+ volts to the 12v supply. I have several but all give the same result.

 

[esp1]

hi frit,
The quick reply is, do you have the pins correctly orientated, ie: are the pins reversed.?
E

 

[Frit]

hi frit,
The quick reply is, do you have the pins correctly orientated, ie: are the pins reversed.?
E

Yep, but I did try reversing them just to see. No smoke and no help!

 

[chuckey]

You should get about .2V, does the lower voltage range on your meter work?
Frank

 

[Frit]

You should get about .2V, does the lower voltage range on your meter work?
Frank

Thanks Frank. The meter was jumping a bit around the zero so I reckoned it was zero. Now I've read the data sheet and it only gives 10 mV per degree so like you say 0.2V at 20 degrees. Only I need ten times that.

 

[Frit]

Checked again this morning and the meter reads only around 4mV for four of the five sensors I bought while the last one (not the one I tried with reverse polarity) reads 12v! I suppose that suggests they're all duds.