From Wideband Amplifier Design

It is useful to have two-port models available for the simplified transistor models introduced in Chapter 2. The model shown in Figure B-1 does not include any reference to C jc or R bb, but these items are easily added later, and there are times you would want to do an analysis without them. C jc is included in the equation for f t (and therefore T t) so the frequency response for the model has not been compromised. I have included R eb because it is an important factor, and it is not always easily added. From this model, we want to derive the two-port h-parameter and the two-port s-parameter model. We will begin with the h-parameter model.

Figure B-1: A simplified model of the type we used extensively throughout the book.

In this model, C ? = T tg m and . Combining these two equations, we get . We will use these relationships in the following analysis.


The h-parameter two-port model is defined as


Multiplying this gives



To solve these, we use the following


By inspection, we see immediately that for the circuit of Figure B-1, h 12 and h 22 are both zero. Using Mathematica to solve node and loop equations derived from Figure B-1, we find that


Given the definition for h 11, we see immediately that


Products & Services
Color Meters and Appearance Instruments
Color meters and appearance instruments are used to measure the properties of paints and coatings including color, gloss, haze and transparency.
Loop Powered Devices

Loop powered devices are electronic devices that can be connected in a transmitter loop, normally a current loop, without the need to have a separate or independent power source. Typical loop powered devices include sensors, transducers, transmitters, isolators, monitors, PLCs, and many field instruments.

GPS Chips and Modules

GPS chips and modules compare signals from several geo-positioning satellites to determine position on the Earth's surface. GPS is an initialism for global positioning system.

Cyclone Separators
Cyclone separators and centrifugal separators utilize centrifugal, gravitational, and inertial forces to remove fine particles suspended in air or gas.
Thermocouple Wire
Thermocouple wire is used to make or extend thermocouples. The wire connects thermocouples from the sensing point to the point of cold junction compensation (CJC).

Topics of Interest

The following was contributed by Dr. Allen Podell (he teaches Advanced Wireless Microwave Techniques at Besser Associates and is an expert in microwave engineering). It is a discussion of how T-coils...

2.7 A LITTLE TOO SIMPLE; ADD BACK R eb AND C jc Unfortunately, the previous derivation is a little too simplistic to model the actual emitter follower when loaded with a capacitance. In particular,...

OVERVIEW The concept of a two-port was informally introduced in Chapter 5 to provide a common framework for the study of transformers and amplifiers. We now reexamine this concept from a more general...

5.5 Simplified Model Equations For Type 1 collisions there are no changes with respect to the exhaustive model and we must define a value of each degradation parameter for each input. Therefore, the...

10.5 HYBRID OR h-PARAMETERS If I 1 and V 2 are taken as the independent variables, the two-port equations may be written as The constants h 11, h 12, h 21, and h 22 are called the hybrid (or h)...