Re: DC relay latching voltage

On 2024-08-25 8:09 a.m., john larkin wrote:

On Fri, 23 Aug 2024 22:05:27 -0700, John Robertson <jrr@flippers.com>
wrote:

On 2024-08-23 12:43 p.m., Don Y wrote:

On 8/23/2024 7:36 AM, John Robertson wrote:

I assume you have the normal back diode across the coil for clamping
the ringing voltage.

If you care about the life of the relay (and how well it "opens"),
a better approach is to add a zener rated at the coil voltage in
series with that diode.  The diode, by itself, delays opening of
the contacts and leads to more opportunities for arcing.  The
zener speeds up this transition.

Hi Don,

Don't you mean that one could use a zener diode in place of the back-EMF
diode - or parallel with it?

We've been using 1N400X (and 3A in some cases)diodes since the 70s for
protecting pinball driver transistors - not too worried about the decay
time so haven't really looked deeper into it before.

Thanks,

John :-#)#

Is there a community of pinball machine people?

rec.games.pinball - but it has pretty much died. When google stopped
regulating posts a few years back it was overwhelmed by crap and was
abandoned by the remaining regulars except for a few diehards.

Nowadays it is the online forums that soak the natterers.

At my new office, the next-door neighbor's husband has pinball
machines, and I invited him over if he needs help with electronics.

If you need manuals/schematics I have hundreds scanned and a couple of
thousand waiting scanning. And there is a great resource site -
https:/ipdb.org for pinball photos, service info, and photos

The downside is that he plays drums too. I don't understand why anyone
would do that. Lotta noise, both cases.

Hope he wears earplugs! And solid state pinball games have volume controls.

John :-#)#


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