Subject: Re: [Shop-talk] Which diodes for a battery charger?

From: David Scheidt <[email-masked]>
Date: Tue, 26 Feb 2013 22:54:05 -0600

On Tue, Feb 26, 2013 at 9:39 PM, Karl Vacek <[email-masked]> wrote:
>
>
> Also - are there positive and negative orientations to the diodes in there
> bow?  They're not marked, and if their polarity is related to label
> orientation, then one pair is mounted with both oriented the same direction,
> while the pair on the other lead are oriented opposite each other.

I'd have to spend some time with a catalog to figure out what you've
got, but diodes definitely are polarity sensitive. That's pretty much
the definition of a diode.  An ideal diode passes current with zero
resistance one direction, and with infinite resistance the other.  It
seems unlikely the factory would have repaired it wrong, but who
knows. Tyically, there's a stripe or band or blob of paint at the
cathode side (negative).  sometimes it's an arrow.  Some use the
length of the pins to tell you, but I don't remember if there's a
standard way to do that or not.

I've run across circuits that have had totally unlabeled diodes too.
Those you test.....

-- 
David Scheidt
[email-masked]
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From: Mark J Bradakis <[email-masked]>
Date: Tue, 26 Feb 2013 22:32:18 -0700

>  Also - are there positive and negative orientations to the diodes in
 >  there bow? They're not marked, and if their polarity is related to 
label orientation,
 > then one pair is mounted with both oriented the same direction, while 
the pair on
 > the other lead are oriented opposite each other.

Are you familiar with a circuit diagram for a diode bridge?  Most likely 
that
is what you are looking at here.

mjb.

[email-masked]