EXPERIEMNT 8
NORTON’S THEOREM
OBJECTIVES:
1. To study the use of Norton’s theorem.
2. To compare Norton’s theorem with Thevenin’s theorem.
DISCUSSION:
Norton’s and Thevenin’s theorems are similar in that both state that any
two-terminal network of resistances and sources of emf may be replaced by a
single source and a single internal resistance.
But Norton consider this source to consists of a generator producing a
constant current equal to the short circuit current at the two terminals of the
original network. The internal resistance has to be in parallel with the constant
current source and is defined in the same manner as the Thevenin’s equivalent
resistance.
Norton’s equivalent circuits are used extensively in the study of electronic
circuits.
INSTRUMENT AND COMPONENTS:
VOM
DC Voltmeter
DC Ammeter
250-ohm resistor
100-ohm resistor
75-ohm resistor
50-ohm resistor
DC Power Supply
Connecting Wires
100-ohm resistor
PROCEDURE:
1. Connect the circuit shown in Fig. 8.2
2. Measure and record the current I in RL.
3. Disconnect RL from the circuit.
4. Measure and record Io, the current indicated by the ammeter
connected across points a and b.
5. Disconnect the voltage source E and replaced it with a short
circuit.
6. Using the VOM, measure the resistance Ro between a and b
7. Compute for the current in RL using the Fig 8.1(b) and designate
this current as I’. Compute the per cent difference between I and
I’. Record these values.
EXPERIMENTAL SET-UP
CIRCUIT DIAGRAMS:
Fig. 8.2 Experimental Circuit
DATA AND RESULTS:
Circuit
Fig. 8.2
COMPUTATIONS
I
Io
Ro
I’
%diff
PROBLEMS:
1. What happens to the terminal voltage of a Norton’s equivalent
circuit when a load resistor is connected to it?
2. What is the difference between a Thevenin’s equivalent circuit and
a Norton’s equivalent circuit?
CONCLUSION: