I bought some TMP36 sensors from Amazon.co.uk for a small project (ESP8266 NodeMCU temp sensors) and have struggled to get sensible output from them

I have tried reading them from A0 on the ESP8266 and reading isolated from the ESP using my DMM. Vs is 3.3v

Output mV readings in both cases are similar.

At room temp = ~800mV (implies 30C - my office is nearer 20)

In iced water = never less than 650mv (implies 15C - it's probably 2-3C)

In how water = never more than 1090mv (implies 59C - it's probably 70-80C)

I've tried all 5 sensors I bought and they are all the same to within about 10mV.

I've tried on the breadboard with the ESP, and on a separate board to prevent heat leak through the board. Also tried with a short 100mm flying lead (no-twist)

I have tried with and without a cap (103 as it's all I have here) across the gnd/Vs and inline resistor on the output. All make no difference.

Am I missing something?
What else could I try? Could I just have a duff batch of sensors being flogged off via Amazon?

Appreciate any suggestions before I go an source some new sensors.

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    \$\begingroup\$ There are three types in the family - are you sure you have the 36? analog.com/media/en/technical-documentation/data-sheets/… \$\endgroup\$ – Dirk Bruere Jan 25 '18 at 17:03
  • \$\begingroup\$ What are you using for a load? \$\endgroup\$ – Trevor_G Jan 25 '18 at 17:11
  • \$\begingroup\$ very nonlinear duds \$\endgroup\$ – Tony Stewart EE75 Jan 25 '18 at 17:25
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    \$\begingroup\$ Change the battery on your DMM. \$\endgroup\$ – Andy aka Jan 25 '18 at 17:28
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    \$\begingroup\$ @Andyaka - +1 fake or failures that should have been binned. Time to return to Azn and source some from a more reputable channel. \$\endgroup\$ – Netgio Jan 26 '18 at 10:03

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