Did I receive Fake TMP36 sensors?

Other Hardware Sensors
1

Hi everyone,

for an upcoming project I purchased ~20 TMP36 sensors from a big Chinese marketplace. Unfortunately, the readings of the analog output have nothing to do with the specs of a TMP36.

To make sure it has nothing to do with my Arduino project and setup I did a test with two AAA batteries, which provide 3.09V (according to my multimeter). With the approximately 22 degrees Celcius in my room, the TMP36 outputs 2.47V, which is well out of the specs of a regular TMP36.

I see two possibilities:

  1. I'm doing something really wrong here
  2. What I received are in fact no TMP36 sensors, but something else

I took pictures of the sensors which you can check.

20240201_195949
20240201_1959491116×1944 426 KB

20240201_195937
20240201_195937912×1724 380 KB

Regarding the measurements:
For measuring the voltage of the batteries I just connected + of the multimeter with the + side of the batteries and ground with ground.
For measuring the output of the TMP36 I connect the left pin (flat side facing me) of the TMP36 with plus of the battery and the right pin with ground of the battery. Measurement was then done between the middle pin and ground.

I hope you can point me in the right direction and either confirm that I received fake TMP36s or there is something else I'm not understanding correctly.

Cheers,
Michael

2

From your description of the test, it seems very likely that you have counterfeit, fake or reject parts.

That is always a major risk with bargain on-line orders, in which case you are simply throwing away money, rather than saving a few pennies compared to buying from a reliable distributor.

Do other examples from that lot behave similarly?

3

I don't trust stuff from "unknown" suppliers, and that includes 3rd-party Amazon sellers. And if you are buying 20 cheap parts it might be a good idea to have a couple of good ones (from reliable suppliers, or previously tested) to compare-to.

I usually like to buy at least one extra part in case one is bad, or in case I don't know, or in case I fry one.

Rejects are probably more likely than outright fakes.

From what I can tell, you've wired them correctly.

4

Thanks! You basically confirmed what I already assumed. I tested all pieces and they all behave pretty much the same. I'll order once again, this time from a trusted supplier.