Jawaharlal Nehru Technological University Hyderabad B.Tech I BASIC ELECTRICAL AND ELECTRONICS ENGINEERING Previous Question Paper (October/November - 2020 - R16)

Electrical sources are broadly classified into two categories based on their ability to maintain voltage or current independent of the load:

1. Independent Sources: These sources provide a specified voltage or current regardless of the circuit conditions. They are further divided into:
   • Independent Voltage Source: Maintains a constant terminal voltage across its terminals, represented by a circle with a + and - sign.
   • Independent Current Source: Maintains a constant current through its terminals, represented by a circle with an arrow indicating the direction of current.
2. Dependent (Controlled) Sources: These sources provide a voltage or current that depends on the voltage or current elsewhere in the circuit. They are represented by a diamond shape and classified as:
   • Voltage-Controlled Voltage Source (VCVS)
   • Current-Controlled Voltage Source (CCVS)
   • Voltage-Controlled Current Source (VCCS)
   • Current-Controlled Current Source (CCCS)

To determine the equivalent resistance between terminals a and b, the circuit must be simplified by identifying series and parallel combinations of resistors. The procedure is as follows:

1. Identify resistors connected in series: If two resistors share a single common node and no other path exists, their equivalent resistance is the sum of their individual values,
   R_eq = R1 + R2
   .
2. Identify resistors connected in parallel: If two resistors are connected across the same two nodes, their equivalent resistance is given by
   1 / R_eq = 1 / R1 + 1 / R2
   or
   R_eq = (R1 * R2) / (R1 + R2)
   .
3. Systematically reduce the circuit by replacing these combinations with their equivalent values, working from the end furthest from terminals a and b back towards the terminals.
4. Continue this reduction process until only a single resistor remains connected between terminals a and b, which represents the total equivalent resistance of the network.