1. Introduction

The hybrid parameters for a two port network characterizing the small signal behaviour of the transistor for an input voltage v1, current i1 and output voltage v2 and output current i2 is shown in Fig. 1 below. This experiment describes the method to measure the following parameters for BJT.

Fig. 1: h parameter representation of a two port network characterizing the transistor small signal behaviour For common emitter configuration the hybrid parameters can be represented as shown in fig.2 below:

Fig. 2. Hybrid parameter representation of common emitter configuration of the transistor

In the present experiment it is planned to measure following parameters for BJT operating at 1MHz frequency: 1) |hl1| or |hie| 2) |hl2| vs |hre| 3) |h21| vs |hfe| 4) |h22| vs |hoe| A complete treatment should also include measurements of the phase response of each of these parameters. However, these measurements are quite difficult and will not be included here.

2. Measurement of h Parameters:

The basic technique of measuring the hybrid, or h, parameter set has been is illustrated below in Fig. 3.

Fig. 3: Basic technique of measuring the hybrid parameter

011

outVin

in

IVh

021

outVin

out

IIh

021

inIout

in

VVh

022

inIout

out

VIh