How Does A Latching Relay Work??

This Old Tony recently did a video about these latching mechanisms. He also made on from scratch to show the principles.

Jessica McIntosh

Thanks for the explanation. Most appreciated.

Far as I'm concerned, you can pull out anything electromechanical from your apparently vast collection and explain it as beautifully and clearly as you explained this relay and have another great video.

Yea, the magnetic latching relays are most common today and they have two coils.

Fran Blanche

Yep, very common.

Fran Blanche

@8Bit Bob it is indeed a relay. Many high-end amps use a relay in the output to protect your speakers during power up. Direct coupled audio amps have big electrolytic caps to D.C. isolate the speakers and they can put a pretty big spike out when first powered on, so a time delayed relay is added to disconnect the speakers long enough for the caps to charge.

HarveyB

Probably at least 10-15 amps, but there's not markings for load.

Fran Blanche

Thanks Fran, that style is a new one on me. I've been in electronics for nearly 60 years and never saw one like it. The vast majority are "set/reset" types using two coils and mechanically held or magnetic types that use a single coil that's pulsed "positive" to set and "negative" to reset. I guess that one would be called a "toggle" type? Time to go catalog surfing to get more info!

HarveyB

Interesting. I've never used one of those latching types before. It's amazing relays are still so widely used electronics today. Many devices needing to switch a high current still use them as they provide better electrical isolation than semi-conductors and are possibly cheaper as well some of the time. Heard a sound suspiciously like a relay click when I turned on my amplifier to watch your video.

Any info/guestimate on what current this thing can switch?

*video

Great video and nicely complementary to This Old Tony's vieo on push latch mechanisms :)

That is very cool just need a couple thousand and id be in business! Thank you for the info

William Nimmo

No worries Fran :-) First again. We have a battery operated digital thermostat (2 AA batteries) and I could hear a relay click and wondered how on earth it could run for 2 years on batteries keeping an relay energised, took it apart, googled the relay part number and so learnt such a thing existed, great idea. The one in thermostat has 3 relay coil contacts, one is common, and then two positives, so you can switch one way then the other. That one you show I guess the other single throw contact is a way to tell which way it is switched so it can be reset to a know position maybe?

Leigh