Norton's theorem

Procedure

Apparatus:

Resistors, Battery, connection wire etc..

Procedure:

  1. Make an electric network using specific resistors and voltage sources.
  2. Determine the current through the load resistance in the original circuit using an ammeter.
  3. Determine the equivalent Norton current INO and Norton resistance RNO.

Steps to find Norton equivalent resistance RNO and current INO:

  1. Calculate the output current for zero load resistance. This gives INO.
  2. Calculate the output voltage V for infinite load resistance (i.e., under open circuit condition).
  3. RNO equals V divided by INO.

An example for Norton equivalent circuit

Step 1: Original circuit.

Figure 9

Step 2: Calculating Norton equivalent current.

Figure 10

Step 3: Calculating the Norton equivalent resistance.

Figure 11

RNO = V / INO = 8 / 0.44 = 18.18 Ω

Now the Norton equivalent circuit is given by.

Figure 12

  1. To make a current source, connect a suitable resistance in series with a voltage source as shown in the last picture.
  2. Construct the Norton equivalent circuit and hence find the load current.
  3. Show that in both cases the load currents are equal, hence verify that Norton's theorem is correct.

Components:

  • Resistor: A resistor is a two-terminal electronic component that produces a voltage across its terminals that is proportional to the electric current through it in accordance with Ohm's law.
  • Lamp: A lamp is a replaceable component such as an incandescent light bulb, which is designed to produce light from electricity. These components usually have a base of ceramic, metal, glass, or plastic, which makes an electrical connection in the socket of a light fixture.
  • Wire: A wire is a single, usually cylindrical, elongated string of metal. Wires are used to bear mechanical loads and to carry electricity and telecommunications signals. Wire is commonly formed by drawing the metal through a hole in a die or draw plate.
  • Switch: In electronics, a switch is an electrical component that can break an electrical circuit, interrupting the current or diverting it from one conductor to another.
  • Battery: A battery or voltaic cell is a combination of many electrochemical Galvanic cells of identical type to store chemical energy and to deliver higher voltage or higher current than with single cells.
  • Voltmeter: A voltmeter is an instrument used for measuring the electrical potential difference between two points in an electric circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage of the circuit; digital voltmeters give a numerical display of voltage by use of an analog to digital converter.
  • Ammeter: An ammeter is a measuring instrument used to measure the electric current in a circuit. Electric currents are measured in amperes (A), hence the name.
  • Non-contact ammeter: A type of ammeter that need not be a part of the circuit.