Latching relay

I need a latching relay with a 12 VDC coil and a SPST switch to operate 120 VAC at no more current than an electric clock. However, I need for this relay to latch ON with just ONE momentary 12 VDC connection to the coil. The relay would then need to latch ON until the same 12 VDC was applied to the SAME coil terminals at which time it would UNLATCH. This relay must have the ability to latch on and off from the same momentary coil connection. Would the Digi-Key relay DS1E-ML-DC12V operate in this manner?


Thank you for contacting Digi-Key , this is a SPDT relay that is a latching type . in the unenergized state pins 7 and 10 will be connected and when energized pin 7 and 12 will be connected it uses the same coil for this operation . it is a 12VDC coil.

​​​​​​​Thanks Craig


Per this datasheet for the series, changing the contact state requires reversing the polarity of the voltage applied to the coil. What you appear to be looking for is more of a toggle function, where sequential applications of the same voltage toggle the relay state back & forth, rather like a click-type pen.

Such products are available, though not particularly common as most folks using relays are interested in being able to apply a known signal and get a known result, rather than one that depends on a prior state.

Flip flops can be used to implement such sorts of toggle functions, and “toggle relay” may be a search term which could surface some ideas for building something to do the task.

Hi @robert ,

Thank you for your inquiry. Agreeing with rick_1976 this particular model, and most all 2A relays or less will require polarity reversal of the single coil in order to change the latching state unless a flip flop or other circuitry is used on the input.

I believe the relay type you are looking for would be “Impulse Relay” as these will change states based on same polarity pulse input. Click Here for 12v options.

Please review datasheets of above links before purchase to make sure they will work for you.