So you are not changing the bias, even though resting current has changed, but
you are changing the conduction angle and thus the class of operation (triode).
Question: How can you change the class of operation and conduction angle with
no change to bias. I appologize, but I am confused.
-------- Original message --------From: "Joe Subich, W4TV" <lists@subich.com>
Date: 10/31/19 19:54 (GMT-05:00) To: amps@contesting.com Subject: Re: [Amps]
Changing class of operation with BIAS > If you increase plate voltage alone,
which results in a higher plate > current with no signal applied, are you
indeed changing the bias? Yes> or no.No. You are changing the operating point
(operating conditions) butnot the bias (unless the bias is generated by a
voltage drop acrossa cathode resistor).In general, in a triode increasing late
voltage will increase theidle current, increase the conduction angle of the
tube and move the operating point more toward class A (class being defined by
conductionangle).On the other hand, in a triode, increasing the grid bias will
decreasethe idle current, decrease the conduction angle and move the
operatingpoint closer to cut-off (class B or class C).73, ... Joe, W4TVOn
2019-10-31 6:54 PM, Mark Bitterlich wrote:> It seems that my original question
generated some interest, and I have> received several private replies. A
majority of them espouse some> interesting viewpoints that make me question
what I thought I knew.> > So I am asking this amplifier theory question again.>
> BIAS is defined as the difference in potential between the cathode and the>
control grid.> > In a zero signal condition, BIAS current is a result of the
difference> described above.> > Thus BIAS can be described by the difference in
voltage between control grid> and cathode or as an indication of plate current
with no signal applied.> > Question:> > If you increase plate voltage alone,
which results in a higher plate current> with no signal applied, are you indeed
changing the bias? Yes or no.> > Thanks,> > Mark> >
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