Ok so, I have a latching relay in my circuit and from what I have found online it should switch when I apply Voltage. So I should be able to get the relay to switch position if I connect one side to ground and the other to a switch which is connected to 5V (for this relay) I tried it like that and I cannot get my relay to switch. What do I need to do to get my latching relay to switch (link to the one I used further down)

(I am using a push button as switch but I also tried supplying voltage for longer and also tried changing the polarity)

(This is my first time using relays so sorry if this is a very newbie question, I couldn't find an answer online)

Link to the relay I am using: https://www.mouser.at/ProductDetail/KEMET/EC2-5SNU?qs=%2Fha2pyFadujLkLw4BdE1nEU29MmNgY0m7tndkTbYK3p3M5hspP5Ibg%3D%3D

Here is how I have it wired up (usb port is connected to a power brick which outputs 5V/1,5A DC, not exactly the correct current but it should still be good enough I think)

enter image description here

  • \$\begingroup\$ Have you measured if you get the 5V when you press your button? often it is the case of wrong pins with simple stuff! and also how do you check if the relay has switched? what pins? do you check for continuity with a meter perhaps? \$\endgroup\$
    – NeuroEng
    Commented Jun 9, 2021 at 17:40

1 Answer 1


It should switch, make sure you are getting 5V on the output of the wires (measure with a Digital Multi Meter) and that you have the pins right and it should work.

The coil takes ~30mA and usb can supply at least 100mA so as long as you have everything connected right it should switch.

Also if you have the single latch type:

Latch type relays should be initialized to a known position before using. Only the specified polarity should be used to energize the coil

enter image description here

From the datasheet

This means if you have the single latch type you need to reverse the polarity


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