[Amps] Amps Digest, Vol 76, Issue 12

[Ulf Tjerneld]

amps-request at contesting.com skrev:

Ian,

Thanks for pointing out that the potential is still *below* chassis ground. Of course it is!

Also, you triode board looks very interesting. I have some reading to do here!

73's

/Ulf


Date: Wed, 8 Apr 2009 17:40:14 +0100
From: Ian White GM3SEK <gm3sek at ifwtech.co.uk>
Subject: Re: [Amps] HV supply question
To: amps at contesting.com
Message-ID: <DToSW8GuNN3JFAmB at ifwtech.co.uk>
Content-Type: text/plain;charset=us-ascii;format=flowed

Ulf Tjerneld wrote:

> >
> >I have noticed when I look on different HV supplys that sometimes the 
> >negative lead is connected to chassis ground and sometimes it is kept 
> >at a potential somewhat above ground by means of a resistor. Can anyone 
> >explain to me why, and if, this is important?
> >
>   

The HV-minus lead (American: B-minus) is often allowed to go a little 
*below* chassis ground potential to permit safe metering of the anode 
current. In a triode amplifier, the grid current can also be measured 
separately.

For more details and diagrams of the current flows, you're welcome to 
download the Triode Board manual from the link below.