Impedance behavior of single-ended and PP networks of amplifiers

Discussion in 'General Electronics Discussion' started by Solidus, May 4, 2013.

1. Solidus

349
4
Jun 19, 2011
This is a rather general question with a more specific application - how does impedance behave in a push-pull network compared to a single-ended output network?

I am eventually going to be working on an RF amplifier using a 4-1000A (eventually* as I have neither the money nor the expertise with HV yet to want to attempt it, just planning now)
. The datasheet prescribes that a push-pull pair running at about 4,500V will demonstrate an impedance of around 9,000 ohms, as the impedance behaves linearly from 4 to 6kV.

Now, the equations for the matching networks involve the input impedance of the network, or the output impedance of the valve. Two ways of putting it. My question being, using the data of a push-pull network, is there a way of construing an approximate value for the plate impedance of one single tube running at the same specifications?

One last question - if the input impedance Z(source) is equal to the quantity R(source) + jX(source), is the source resistance equal to the plate resistance Rp? That can be derived from the mu and transconductance, both of which are much easier values to find.  