Re: HF Gain Stepping RC Network Calculator

On Thu, 29 May 2008 15:39:07 -0500, John Byrns <byrnsj@xxxxxxxxxxxxx>
wrote:

Here is a more complex and perhaps more interesting and useful "RC
Network Calculator" based on Iain's work. This one calculates and plots
the response of the type of High Frequency Gain Stepping RC Network that
Patrick likes to use in stabilizing amplifiers when applying NFB.

The calculator can be found here;

http://fmamradios.com/HF%20Step%20Network%20Calculator.xls

There are 5 component values that must be entered.
C is the capacitor in the series RC of the HF gain stepping network
R is the resistor in the series RC of the HF gain stepping network
rp is the anode resistance of the tube to which the network is connected
Rp is the load resistor of the tube to which the network is connected
Rg is the grid resistor of the following stage

I am sure there are many bugs in this first pass, perhaps some serious
ones, I would appreciate feedback relating to any bugs that may be
detected.

If I understand right, you have a series connection of C and R, and this
series CR network is placed in parallel with rp, Rp and Rg.

Just picking a spot frequency of 5000 Hz for a test, if I work out the
impedance of all that, I get a real part of 16583.81, which matches what
your Excel *** shows, but I get an imaginary part of -4530.698, which
doesn't match.



Regards,

John Byrns

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