Network analysis finds the voltages across and the currents through all network components. There are various techniques for calculating these values. In series-parallel circuits, the total resistance, the voltage of the battery, and the total current can be calculated using Ohm’s Law.
Due to the presence of two voltage and current sources, there is no way to calculate total resistance in the case of a two-battery complex circuit. The total current splits into unknown proportions at each bridge in an unbalanced bridge circuit, making further calculations impossible. So, when faced with multiple unknowns in a circuit, we use a mathematical process known as systems of equations. The various unknowns are solved in this process by relating them to each other in multiple equations. When solving multiple unknowns, we must use the same number of equations as the number of unknowns to find a solution.
Read More – Network analysis.
Important Questions with Answers
1. What is resistance?
Resistance can be defined as the property of a conductor that opposes the flow of electric current. It is also defined as the voltage applied divided by the current flowing through it.
2. State and explain Ohm’s Law.
Ohm’s Law states that the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperatures remain constant.
In mathematical form, this current-voltage relationship is written as,
V=IR
In the equation, resistance R is the proportionality constant and has units of Ohms, with the symbol Ω.
3. What is a component?
The component is a device with two, three or more terminals into which the current may or may not flow.
4. ________ is a point at which two or more terminals of components are joined.
a. Branch
b. Node
c. Port
d. Mesh
Answer: b. Node
Explanation: Node is a point at which terminals of more than two components are joined.
That’s why option B is correct.
The branch is a component joining two nodes. Mesh is a group of branches within a network joined to form a complete loop so that there is no other loop contained within it. A port is nothing but two terminals where the current into one is identical to the current out of the other.
5. What is a capacitor?
A capacitor is a device that stores an electric charge and is made up of one or more pairs of conductors separated by an insulator.
6. Why are resistors used?
A resistor is a two-terminal electrical component that provides electrical resistance. In electronic circuits, resistors are predominantly used to lower current flow, divide voltages, block transmission signals, and bias active elements.
7. What is a series-parallel circuit combination? How do you identify a series-parallel circuit?
A combination circuit allows electricity to flow through a “combination” of series and parallel paths. Its properties are a combination of the two. If all current flowing through one resistor enters another, the two resistors are in series. If the voltage across one resistor is the same across another, the two resistors are in parallel.
8. Resistivity of a wire depends on __________.
a. the length of wire
b. the cross-section area
c. the material
d. the thickness of the wire
Answer: c. the material
Explanation: The resistivity of a wire is constant, and it depends on the type of material used.
9. A conductor is said to have a resistance of 1 Ohm. A potential difference of 1 V across its terminals causes a current of X ampere to flow through it. What will be the value of X?
a. 4
b. 6
c. 1
d. 5
Answer: c. 1
Explanation: We know Ohm’s Law states that the potential difference (voltage) across a conductor is proportional to its current and Resistance (R) is the constant of proportionality.
According to Ohm’s Law,
V = IR
Where,
V – potential difference between two points which include a resistance R.
I = V/R
I= 1V/1Ω = 1A.
10. How do you analyse an electrical circuit?
Ohm’s Law is the most important in circuit analysis. According to Ohm’s Law, the voltage through an element is equal to the element’s current multiplied by the current flowing through the element, or in mathematical terms,
Voltage = Current x Resistance,
i.e. V = IR.
Voltage (V) measures electric potential in volts (V).
Practice Questions
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When do we use three-terminal resistors?
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What are the four types of circuits?
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What are circuit parameters? Give some examples.
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Which is a two-port device?
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What is a bridge circuit, and what are its advantages?
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