Basic Electrical Engineering Interview Question

Q. What is an Electric circuit?

A. An electric circuit is an inter connection of electrical elements.

Q. What do you mean by independent and dependent sources?

A. An ideal independent source is an active element that provides a specified voltage or current that is completely independent of other circuit variables where as an ideal dependent source is an active element in which the source quantity is controlled by another voltage or current.

Q. What are the types of dependent sources?

A.1.Voltage controlled voltage source
2. Current controlled voltage source
3. Voltage controlled current source
4. Current controlled current source

Q. Explain ohm’s law?

A. At constant temperature, current flowing through an element is directly proportional to the potential difference across it.

Q. What is open circuit and short circuit?

A. An open circuit is a circuit element approaching infinite resistance and short circuit is a circuit element with resistance approaching zero.

Q. Define a branch, node, loop and mesh?

A. Branch: It represents a single element such as voltage source or resistor.
Node: A node is the point of connection between two or more branches
Loop: A loop is any closed path in a circuit
Mesh: A mesh is a loop which does not contain any other loops in it.

Q. State kirchhoff’s laws?

A. Kirchhoff’s current law:
It states that algebraic sum of currents entering a node is zero.
i.e
Sum of currents entering a node=sum of currents leaving it.
Kirchhoff’s
voltage law:
It states that algebraic sum of voltages around a closed path or loop
is zero.
i.e
sum of voltage drops=sum of voltage rises.

Q. What is super node and super mesh?

A. A super node is formed by enclosing a voltage source between two non-reference nodes and any elements connected parallel with it. A super mesh results when two meshes have a current source in common

Q. Mesh analysis vs Nodal analysis?

A. Mesh analysis is more useful when there are many series elements, voltage sources and we have to find out branch or mesh currents. Nodal analysis is better if there are many parallel connected elements, current sources and we have to find node voltages.

Q. Explain superposition principle?

A. The superposition principle states that the voltage across (or current through) an element in a linear circuit is the algebraic sum of voltages across (or currents through) that element due to independent sources acting alone.

Q.
What is meant by source transformation?

A. A source transformation is the process of replacing a voltage source V_s.
in series with a resistor R by a current source i_s
in parallel with a resistor R, or vice versa.

Q. State thevenin’s theorem?

A. Thevenin’s theorem states that a linear two terminal circuit can be replaced by an equivalent circuit consisting of a voltage source V_TH
in
series with a resistor R_TH
where
V_TH
is open circuit voltage at the terminals and R_TH
is the input or equivalent resistance at the terminals when the independent sources are turned off.

Q. State Norton’s theorem?

A.
Norton’s theorem states that a linear two terminal circuit can be
replaced by an equivalent circuit consisting of a current source I_N
in
parallel with a resistor R_N
where
I_N
is short circuit current through the terminals and R_N
is
the input or equivalent resistance at the terminals when the independent sources are turned off.

Q. State maximum power transfer theorem?

A.
Maximum power is transferred to the load when load resistance equals
thevenin resistance as seen from the load.

Q. Explain the behavior of capacitor and inductor to D.C?

A.
A capacitor acts as an open circuit to D.C
We
know that Q=CV
i=dQ/dt
i=CdV/dt
dV/dt
is zero in case of D.C supply. So current is zero which implies it
acts as an open circuit.
An
inductor acts as a short circuit to D.C
We
know that V=Ldi/dt
di/dt=0
in case of D.C supply. So, voltage across inductor is zero which
implies it acts as a short circuit.

Q. What are different parameters used to represent two port networks?

A.A two port network can be modeled using six parameters Impedance (Z),Admittance (Y),Hybrid (h),Inverse hybrid (g),Transmission (T) and Inverse transmission (t) parameters.