I purchases a tube of EA2-3NJ relays from Mouser. Reputable company, not counterfeit parts, yada yada. I try using them with 3.3V coming off a Raspberry Pi and they won't switch. I tried several other 3.3V sources, can't get them to switch. I tried 10 different ones from the sleeve, no luck. Contacted Mouser, after a little back and forth, they sent me a replacement set. Same issue.

Here is the datasheet. The coil wants to be connected one way (+/-) and I am sure I am connecting it that way. I am not using a pulsed or waveformed voltage. The 3V model that I am using has a Must Operate Voltage of 2.25V. I tried voltages down to 2V and as high as 5V. Never switched. The contacts will handle 1A at 30V, I was using 5V connected to a couple of LEDs to test the circuit. I tried it both with and without a flyback diode.

So, I don't know what else to try. It's a relay, it's not rocket science. The only thing I can find in the datasheet that might suggest a problem is related to storage time -- no more than 3 months at 70% relative humidity or 6 months at 50% relative humidity. So, could I have received two bad batches from Mouser or am I doing something wrong?

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    \$\begingroup\$ Can your voltage sources handle the current, about 50 ma at 3 volt? \$\endgroup\$ – Robert Endl Mar 17 '18 at 1:41
  • \$\begingroup\$ Yeah, in line with what @RobertEndl asked, connect the relay coil to your 3.3V source and then while it is connected use your meter to measure that actual voltage across the coil. If your source is weak or current limited in some way the voltage at the coil may read way lower than what you thought. Don't have a multi-meter? If not then now would be a time to get a digital multi-meter. Essential tool for working with this stuff. \$\endgroup\$ – Michael Karas Mar 17 '18 at 1:47
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    \$\begingroup\$ Did you try to connect the coil in opposite way? \$\endgroup\$ – Ale..chenski Mar 17 '18 at 3:06
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    \$\begingroup\$ OMG! I don't know why I never tried that. Apparently the diagrams in the datasheet are of the relay turned upside-down with the pins up, not from the top down like I always assumed. And there are no markings or square solder or anything to suggest which is pin 1. Thank you @AliChen. If you want to post your comment as an answer I will give you the credit. \$\endgroup\$ – ThatAintWorking Mar 17 '18 at 3:18
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    \$\begingroup\$ The data sheet clearly says "Bottom View" on the page showing the pin layout, and another drawing shows a "pins 1 and 10" marking on the top of the relay. \$\endgroup\$ – Peter Bennett Mar 17 '18 at 6:06

This kind of small relays are frequently have pre-polarized primary coil, to reduce the switch effort. And there could be a flyback diode inside as well. The datasheets show the bottom view of relays. And the application section states,

If the internal connection diagram of a relay shows + and − symbols on the coil, apply the rated voltage to the relay in the specified direction.

So, if it doesn't work, it is likely a misunderstanding of relay pinout, just try the opposite polarity.

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