Experiment Description

Experiment

Experiment E19    Investigation of the Characteristics of a Transistor (A)


Objectives
  • Use a multimeter to test a transistor
  • Investigate the input characteristics of an n-p-n transistor
  • Investigate the current transfer characteristics of an n-p-n transistor
Description
In this activity, you will investigate the input characteristics and the current transfer characteristics of a transistor. You will learn to test a transistor using a multi-meter.

Since a transistor consists of two p-n junctions, current would only flow in particular directions and not the other way round. In Experiment 1, a multimeter set to act as an ohmmeter has a built-in battery that produces current. Whether the meter deflects or not indicates the conductivity between its terminals. Therefore, you will use it to test the transistor.

In Experiment 2, you will test the use of an electrometer by varying the output voltage of a potential divider. You will verify the electrometer reading by an ordinary voltmeter connected in parallel. The electrometer will be used in Experiment 3.

In Experiment 3, you will apply different currents to the input (base terminal) of a transistor and measure the corresponding input voltage VBE using an electrometer.

In Experiment 4, you will study how the collector current varies with the base current of a transistor. The base current is controlled by the potential divider with maximum voltage 3 V.

Apparatus
n-p-n transistor [1]
base meter (100 mA) [1]
ammeter (1 mA, 5 mA and 10 mA) [1]
electrometer [1]
voltmeter (1 V, 5 V and 10 V) [2]
variable resistor (0 - 5 kOhm) [1]
resistor (15 kOhm) [1]
battery box with 2 dry cells [1]
battery box with 4 dry cells [1]
multimeter [1]
Experiment