Latching Relay EC2 Low Current Coil Gold Alloy Contact DPDT 250V 2A 3V 5V or 12V Coils

This is a new, miniature electromechanical relay made by NEC-Kemet.

It is available in several coil voltages as shown in the variations. It is a twin-coil, latching type and has a very low coil drive power of 140mW while maintaining a respectable maximum current rating in the DPDT contacts. The contacts are gold alloy over silver alloy and are designed for telecoms applications with contact currents down to 10uA. This makes them suitable for good quality audio use. This contrasts with other contact types where a minimum current is required in the contacts to clean them on each switching operation.

What's a latching relay? In a standard relay the contacts move to the 'on' position when the coil is energised and return to the 'off' position when the coil voltage is turned off. In a latching relay, a momentary operation of the 'on' coil moves the contacts over to the 'on' position where they stay, even when the coil power is removed. To turn them back to the 'off' position, the 'off' coil has to be energised for a moment and then the contacts stay in that position once more. This electromechanical cleverness saves driving power into the relay coil all the time and can be very handy for other reasons, such as retaining their position during a power failure, or when the computer card driving them is turned off for the night. Or crashes.

You can see an example of how to make a radio station studio switcher using these and the TNU latching types at the following link:

The Radio Glen Transmit Selector

As far as I know, with some computer control modifications, that's still being used after twenty years.

Headline Data

EC2-3TNU
Coil resistance, 3V coil: 64 Ohm
Coil current, 3V coil: 47 mA

EC2-5TNU
Coil resistance, 5V coil: 178 Ohm
Coil current, 5V coil: 28 mA

EC2-12TNU
Coil resistance, 12V coil: 1028 Ohm
Coil current, 12V coil: 12 mA

Max switching voltage: 220 VDC / 250 VAC
Max switching current: 2 A
Max carrying current: 2 A
Max carrying current: 2 A