Experiment Description

Experiment

Experiment E22    Transistor as a Switch

Objectives
  • Investigate the switching property of a transistor
  • Setup a circuit using transistor to turn on a light bulb in darkness
  • Setup a circuit using transistor to turn on a light bulb at high temperature
Description
In this activity, you will make use of the switching properties of a transistor to construct circuits that will turn on/off another circuit when the condition changes.

In Experiment 1, you will test whether the transistor module will switch on/off the secondary circuit as the input voltage Vin is varied by the potentiometer.

In Experiment 2, you will use an LDR and a transistor module to switch on/off a bulb in the secondary circuit automatically.

In Experiment 3, you will use a thermistor and a transistor module to switch on/off a bulb in the secondary circuit automatically.
Apparatus
n-p-n transistor module (15 kOhm base resistor, relay switch) [1]
variable resistors (1, 5, 10, 50 kOhm) [1 each]
voltmeter (5 V and 10 V) [1]
multimeter [1]
light dependent resistor (LDR) [1]
thermistor [1]
battery box with 4 dry cells [1]
12 V low voltage power supply [1]
light bulb (12 V) [1]
torch [1]
cardboard [1]
water in a beaker [1]
ice in a beaker [1]
busen burner [1]
Experiment