## Norton’s Theorem MCQ (Interview-Exam) Question-Answer

**Q.1** The Norton current is the_______.

**A.** Open circuit current

**B.** Neither open circuit nor short circuit current

**C.** Short circuit current

**D.** Open circuit and short circuit current

**Ans : **Short circuit current

**Q.2** Norton resistance is found by?

**A.** Opening all current sources

**B.** Opening all voltage sources and shorting all current sources

**C.** Shorting all voltage sources

**D.** Shorting all voltage sources and opening all current sources

**Ans : **Shorting all voltage sources and opening all current sources

**Q.3** In Norton’s theorem Isc is__________.

**A.** A single current source

**B.** 0

**C.** Sum of two current sources

**D.** Infinite current sources

**Ans : **A single current source

**Q.4** Norton’s theorem is true for __________.

**A.** Non-Linear networks

**B.** Neither linear networks nor non-linear networks

**C.** Linear networks

**D.** Both linear networks and nonlinear networks

**Ans : **Linear networks

**Explanation: ** I=V/R. Total resistance R = 20+40=60ohm. V=120V. I=120/60=2A.

**Q.5** Can we use Norton’s theorem on a circuit containing a BJT?

**A.** No

**B.** Insufficient data provided

**C.** Yes

**D.** Depends on the BJT

**Ans : **No

**Q.6** Isc is found across the ____________ terminals of the network.

**A.** Output

**B.** Either input or output

**C.** Input

**D.** Neither input nor output

**Ans : **Output

**Q.7** Calculate the short circuit current is the 5 ohm resistor is the load resistance.

**A.** 0.32A

**B.** 0.67A

**C.** 0.72A

**D.** 0.83A

**Ans : **0.72A

**Explanation: ** I=V/R. Total resistance R = 20+40=60ohm. V=120V. I=120/60=2A.

**Q.8** Calculate the Norton resistance for the following circuit if 5 ohm is the load resistance.

**A.** 11 ohm

**B.** 13 ohm

**C.** 10 ohm

**D.** 12 ohm

**Ans : **12 ohm

**Explanation: ** Shorting all voltage sources and opening all current sources we have:

RN=(3||6)+10 = 12 ohm.

**Q.9** Which of the following is also known as the dual of Norton’s theorem?

**A.** Superposition theorem

**B.** Millman’s theorem

**C.** Thevenin’s theorem

**D.** Maximum power transfer theorem

**Ans : **Thevenin’s theorem

**Q.10** Find the current in the 5 ohm resistance using Norton’s theorem.

**A.** 1.5A

**B.** 0.5A

**C.** 1A

**D.** 0.25A

**Ans : **0.5A

**Explanation: ** I=V/R. Total resistance R = 20+40=60ohm. V=120V. I=120/60=2A.

## Norton’s Theorem

**1. Theoretical Basis:** Norton’s Theorem is based on the idea that any linear electrical network can be replaced by an equivalent circuit comprising a current source in parallel with a resistor.

**2. Equivalent Norton Current (I_N):** In Norton’s equivalent circuit, the original circuit’s complex network is replaced by a single current source (I_N) connected in parallel with an equivalent resistor (R_N).

**3. Source Transformation:** Norton’s Theorem is closely related to Thevenin’s Theorem, and the two can be used interchangeably through source transformations. Norton’s equivalent current source is mathematically equivalent to Thevenin’s voltage source, and vice versa.

**4. Norton Current Calculation:** The Norton current (I_N) is calculated by short-circuiting the terminals of the original circuit and determining the short-circuit current flowing through the shorted terminals. This current becomes the Norton current.

**5. Norton Resistance Calculation:** The Norton resistance (R_N) is found by deactivating all independent sources in the original circuit (replacing voltage sources with short circuits and current sources with open circuits) and determining the equivalent resistance across the output terminals.

**6. Simplification of Circuit Analysis:** Norton’s Theorem is particularly useful for simplifying circuit analysis, especially in cases where the circuit contains multiple interconnected components. It allows engineers to focus on the behavior of a single current source and a resistor.

**7. Application in Circuit Design:** Norton’s Theorem is often applied in circuit design and analysis to determine the behavior of circuits under different conditions. It aids in understanding the impact of changes in load conditions on the overall circuit performance.

**8. Limitations:** Norton’s Theorem is applicable only to linear circuits, and the components within the circuit must be linear and follow Ohm’s Law. It is not suitable for circuits with nonlinear elements.

**9. Parallel Combination:** Norton’s equivalent circuit essentially represents a parallel combination of the Norton current source and the Norton resistor. This simplification facilitates easier analysis of the circuit.

**10. Practical Use:** Engineers commonly use Norton’s Theorem in various applications, such as electronic circuit design, power systems analysis, and troubleshooting, to simplify complex circuits and facilitate easier calculations.