Now That's What I Call A Flip-Flop!!

Interesting... magnetic flux at work!

Fran Blanche

No idea.

Fran Blanche

Mechanical NVRAM!

Circuitmike

You could also call it a Set/Reset Latch because it remains in the new state without any power applied.

Bart de Boisblanc

Very nice little device.

Jessica McIntosh

Beautiful! They are still relatively common. I use one of these bi-stable relays in a product: http://www.farnell.com/datasheets/1922599.pdf

Ben

Notice the copper 'slug' on the pole face - that delays the operation of the relay - often used in the old mechanical relay and motor telephone exchanges.

This mechanical flip flop relay still exists today in very expensive military/aerospace relays that are very small and hermetically sealed within a soldered can. I never opened one up to see how it worked, but they must be similar to the locking action your relay has. I can hear the "click" of one relay coil engaging and applying power to that coil repeatedly doesn't result in any change or sound. Energizing the 2nd coil makes the "click" and switches the contacts, just like your relay. I use them in circuits where a system failure would engage one of the coils with a single pulse and the contacts would illuminate a light, or sound a simple alarm. There would be a reset button on a control panel that would engage the other coil and snap it back into the non-alert mode. So they're great for sending a warning signal that demanded an operator acknowledge the fault and push the "ALARM CANCEL" button. If the fault is still present, and holding the latch in the "ALARM" position, trying to reset it with the 2nd coil would only result in the alert still appearing because the "ALARM" coil would still be energized and would not release to the "ALARM RESET" coil. And with all power removed, the latch stays in the position it was last left in, so there is a memory of sorts that the circuit had a fault when turned off. It's a very convenient relay for alarm setting and alarm reset. Again, they're in tiny hermetically sealed housings and I never tried to open one up like a can of tuna. Your example is large and easy to see operate. Very cool! I've never seen one of these mechanical wonders all exposed that way. Thanks for sharing!

Matt Wietlispach

C'mon Fran...Hook it up astable. Watch the fun. I did it with mine. (28 VDC, though). Very cool. Use some caps across the coils, though.

Chuck Kirchner

I have two of these, sort of. My two have the relays vertical, but essentially work the same. I'm not sure, but I believe mine to be from a Gates/Harris 25KW FM transmitter I decommissioned a few years back. They were to latch a safety circuit if a fault occurred, and they had to be electrically reset for the transmitter to be fired up again.

Chuck Kirchner

lovely little gizmo.

Neat! Any ideas where this would have been used? And there sure are a lot of cutoff wires at the top there.

Mark Sundstrom

Hey thats cool

William Nimmo

Neat!

Great Joe

It could be considered a mechanical memory device as it holds its last state even after the power is lost. I wonder as to where it was used.

Michael A Klaene

I love the mechanical memory in this. If you have enough of them you could use them to write (simple) programming, as you can manually flip-flop a bit, and it would even be stored if power fails.

CH23

I would say this is a true flip flop, I was ging to ask why, but I think you're spot on with failsafe!

Dr Andy Hill

What was it for originally?