Unit-1

DC Circuits

Q1). For the circuits given below write the voltage equations:

Solution: Let current i1be in loop 1 current and i2 for loop 2 

Q2) Write the loop equations for the circuit given below?

Solution:

For loop 1 

For loop 2 

Q3) Using nodal analysis find voltage across 5 ohm resistor.

Solution:

For V1

1

For V2

2

Solving 1 and 2:

For 5 voltage =

= -50.9 + 57.27

= 6.37V

Q4) Find the current through resistance.

Solution:

1= 0

2=

1 + 2 

Special Case:

Since two voltage sources with different magnitude in parallel which cannot be connected as in single branch two different current is not possible (if 5V than I = zero).

Q5) Find I using Superposition theorem?

1 =

2 =

=

1 + 2

=

Q6) Apply Thevenin’s theorem and find Vth and Rth?

Answer:

Finding Isc from circuit directly:

By KCL,

Q7) Find Vth and Rth for circuit below?

Answer

Also, clear from circuit that Vth = 1V.

By applying KVL we get,

1-3Isc=0

Isc=A

Q8) Find Rth and Isc for circuit below?

Ans;

Rth=3k+2k=5k

By applying KVL we get

Therefore,

Q9) Find VX for circuit below?

Solution: For Rth

By KCL,

     But,

By KVL,

Q10) Find Rth?

Solution: Since, no independent source is present so,

Isc = 0

And we know that,

Since Rth cannot be zero

       But

Q11) Find out the Norton’s equivalent

Solution:

Since, there is no significance of current source

A

Q12) Find out the value of load resistance if power absorbed is maximum.

Solution: find Thevenin’s equation

Q13) Find maximum power delivered is RL if its value is

1. 16Ω
2. Ω
3. 60Ω
4. 20Ω

Solution

Therefore,