[AMRadio] Component ID please


John E. Coleman (ARS WA5BXO) wa5bxo2006 at pctechref.com
Mon Dec 11 11:40:44 EST 2006


No, look again, it is internal series multiplier, so that the meter will
read volts with a direct hookup.  If this is a 0-500 Volt meter as the
picture seems to indicate, and multiplier was 500,000 ohms then the meter
movement would have been a 1ma movement.  I see no reason for a capacitor to
bypass the resistor, maybe the meter but not the resistor. So perhaps the
other device was another resistor to adjust the value so that the meter is
more accurate than it was with just the one resistor.  It may also be for
temperature compensation.  Both could be removed and the one milliamp
movement used with an external resistor arrangement or divider.  With the
proper circuitry and switch it could be a 0-500 milliamp or 0-5KV.

John, WA5BXO 

-----Original Message-----
From: amradio-bounces at mailman.qth.net
[mailto:amradio-bounces at mailman.qth.net] On Behalf Of Rick Brashear
Sent: Monday, December 11, 2006 10:28 AM
To: Discussion of AM Radio in the Amateur Service
Subject: Re: [AMRadio] Component ID please

Jack...
That looks more like a shunt to me.
Rick

Jack Schmidling wrote:

> The HV meter on my supply does not work and the series resistor inside 
> seems to be open.  No problem but there is another component across 
> the resistor that I have never seen before and assume is a cap but 
> don't know.. it also reads open.
>
> I posted a pic at http://schmidling.com/meter.jpg for ID.
>
> As an aside, the resistor is quaintly marked "Precision" but the value 
> is "1/2 meg" which is hand written in like at NBS.  No decimal point, 
> just 1/2 meg.  What is really bazaar is the accuracy is 2%, also hand 
> written.  When was that ever precision?
>
> js
>

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