Timeline for Identify unknown transistor (possibly faulty LM35 temperature sensor)
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jan 3, 2015 at 10:58 | comment | added | Arc676 | @MichaelKaras If attempting to measure properties of an LM35 as if it were a transistor can damage it, it is very probable that what I now have is a faulty temperature sensor. | |
| Jan 2, 2015 at 12:33 | comment | added | Michael Karas | It may be possible that the part in the OP's hand has become bad because of attempts to measure the hFE as a transistor. If the part had been hooked up with more than 0.2V in a reverse connection between GND and +Vs the part may have been damaged. The data sheet cautions that the absolute negative voltage limit on the +Vs pin is -0.2V. | |
| Jan 2, 2015 at 10:15 | comment | added | Wouter van Ooijen | Or be a bit more brutal: hold a match flame next to it (don't tough it, just a few mm distance, or spray liquid air over it. | |
| Jan 2, 2015 at 10:05 | comment | added | Ignacio Vazquez-Abrams | Or you may not have applied enough heat long enough. Try holding it between your thumb and index finger. | |
| Jan 2, 2015 at 9:59 | comment | added | Arc676 | I followed the diagram on the 2nd page (TO-92 package) and wired it up to the GND and 5V on my Arduino. I connected a 10k\$\Omega\$ resistor to the output pin and added an LED. I measured the voltage across the resistor, but it didn't change when I breathed on it (2.7V). However, when I reversed the GND and 5V pins I got -2.4V. However, it's possible that I have a faulty temperature sensor instead of a faulty transistor. | |
| Jan 2, 2015 at 9:46 | comment | added | Ignacio Vazquez-Abrams | @Arc676: en.wikipedia.org/wiki/TO-92 | |
| Jan 2, 2015 at 9:41 | comment | added | Arc676 | Testing as of posting this comment. What's "TO-92"? | |
| Jan 2, 2015 at 5:48 | comment | added | Spehro 'speff' Pefhany | +1 LM35DZ is the lowest (worst) accuracy grade and TO 92 case of LM35. | |
| Jan 2, 2015 at 5:43 | history | answered | EasyOhm | CC BY-SA 3.0 |