[Heathkit] meter protection

[Dennis Berry]

I have seen on several websites that advocate putting the back to back diodes on a meter, which I am not rejecting as wrong, but I do have a question.

As I recall most of the Heath meters are about 1200 ohms and 200 uA movements.  Wouldn't this indicate full meter movement is at 0.24V?  Do diodes that conduct up to say 0.5V or 0.6V still protect the meter?  I know it's better than a flashover voltage, but is 0.5V enough to still damage the meter?

Just trying to learn and understand, not pick on the method or Cal.

Thanks in advance,

Dennis, NU8S

>  Message: 1
>  Date: Tue, 13 Oct 2009 16:25:16 +0000 (GMT)
>  From: C E <catman351 at yahoo.com>
>  Subject: [Heathkit] SB-200 meter flashover/diode protection
>  To: heathkit at mailman.qth.net
>  Message-ID: <190179.86540.qm at web37103.mail.mud.yahoo.com>
>  Content-Type: text/plain; charset=iso-8859-1
>
>  All:
>  I noted Bill's comment on his friend's SB-200 meter flashover: "A friend of mine is looking for the meter (working) for his SB-200 - > apparently he had a flashover while tuning it up that took out his meter."
>
>  It would be cheap insurance to install a set of back-to-back diodes on your SB-200?multi-meter to mitigate the damage caused by such
>  problems. One can replace diodes all day...meters, unfortunately, are another matter.? FWIW.
>  Cal, N6KYR/4