On 1/14/2011 10:50 AM, Antonio Vernucci wrote:
Antonio - I think you slipped a decimal point. The parallel equivalent
of the series combo 58R-2947j is actually 149k+2948j.

Hi John,

I do not understand where your -2947j figure comes from. I see it
appearing nowhere in my calculations.


Well, it's not mine and it appears in you post as 54 pF. Isn't 58R in
series with 54 pF equal to 58-2947j? And isn't the parallel equivalent
of that equal to 149k ohms of resistance in parallel with -2948 ohms of
reactance (~54 pF)?

I'm pointing out that you slipped a decimal point or you would have seen
that 54 pF is too much it results in the parallel equivalent resistance
of 149k rather than 1.49M. Mike's figure of about 18 pF (17 pF series
combination) will do the job.

In any case, parallel -- series trasformations never result in a
change of the reactance sign; therefore it is not possible that a -2957j
(negative) reactance is transformed into a +2948j (positive) reactance.

You are correct. I allowed the sign of the suseptance to creep through.

73

Tony I0JX