Got a link to a single-coil permanent magnet alternate-action latching relay?
"The logic signal is buffered with the NPN transistor that then drives relay switch S1. You should use a latching relay, which uses permanent magnets to hold the armature in place after the drive current is removed."
And if so, how would that make any sense in this application?
John
Ledex used to make them. They still make the rotary solenoids that drove them. They didn't need a permanent magnet. The rotary solenoid was linked to a standard rotary switch.
Well, I vaguely remember a single-coil magnetic latching relay that needed a reversed current to reset. But, that isn't used in the schematic they presented nor would it be easy to implement, I think.
John S
We use tens of thousands of them. Fujitsu FTR-B3GB4.5Z-B10 for example. They consume zero standby power, and thermal EMFs are correspondingly zero.
I posted this cute little driver circuit here a while back...
ftp://jjlarkin.lmi.net/V490_Relay_Driver.jpg
John
For some reason, I can't see the entire schematic. It appears to the the upper-left corner.
John S
Right. That's the relay driver part.
John
...
Wish you had a web photo site, I still cannot get ftp, different wireless Internet (my mobile phone) but same (Telstra) network, same error :(
Cheers, Grant.
circuit.
Now that i recheck, there was no PM. Strictly a mechanical thing.
?-)
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