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Re: [Amps] HV Divider, Problem Solved

To: "KB0NLY" <kb0nly@mchsi.com>, <amps@contesting.com>
Subject: Re: [Amps] HV Divider, Problem Solved
From: "Bob Maser" <bmaser@tampabay.rr.com>
Date: Sun, 1 Mar 2009 20:25:08 -0000
List-post: <amps@contesting.com">mailto:amps@contesting.com>
I gave you the answer in my previous.  Read about measuring voltage using a 
ammeter, which is what you are really doing.  Find a 1ma full scale AMMETER 
and use 5 megohms in the meter multiplier string.  When you connect the 
AMMETER across the 100K ohm resistor and it will give you a full scale of 
5000V(1MA on the AMMETER.  If you insist on using the 10 megohm string then 
you will have a meter that is giving you a full scale of 10,000 volts.  Read 
the Handbook.
Bob W6TR
----- Original Message ----- 
From: "KB0NLY" <kb0nly@mchsi.com>
To: <amps@contesting.com>
Sent: Sunday, March 01, 2009 8:15 PM
Subject: [Amps] HV Divider, Problem Solved


Well i don't know how this amp was working before i started the 
modifications but i pulled the resistor from B- to chassis ground, at an 
AMPS member suggestion, to measure it, it was open!  So i grabbed an new 
wirewound vitreous resistor out of the drawer and put it into place and it 
now works perfectly and i have 11.68v off the divider.

I'm not totally clear on the math here though, so if someone wanted to 
comment here is my remaining question..

I have 10 1M ohm resistors in series, so 10,000,000 ohms, and i have 11.68v 
off the divider.  How do i reverse the math to determine the value of the 
high voltage knowing the output of the divider?  See what i'm saying?  I 
know what i measured before using the HV meter, and i know what i have after 
the divider, just wanted to see if they match up.

I have a level that will work with the board now, but i want to understand 
it better.

Thanks and 73,

Scott KBØNLY

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