Apply Mesh Analysis to solve for currents
Thevenin circuits
Apply Nodal and Superposition to solve currents
Determine the current 𝐼𝐼 in the circuit given in figure 1 by using Delta-to-Star Transformation to
simplify the network.
Figure 1: Circuit for question 1.1
Chapter 4
1. In the circuit given in figure 1 below, after some time the switch moves
to the position as indicated at time 𝑡𝑡 = 0. Given that 𝑅𝑅 = 5𝑘𝑘Ω, 𝐶𝐶 = 3 𝜇𝜇𝜇𝜇,
answer the following:
FIGURE 1
1.1
Write an expression for 𝑉𝑉𝐶𝐶 (𝑡𝑡), given that the initial voltage is 2.5 V
1.2 What is the final voltage of across capacitor – i.e. 𝑉𝑉𝐶𝐶 (𝑡𝑡 = ∞)
(4)
(2)
1.3
Calculate the voltage at the time constant – i.e. 𝑉𝑉𝐶𝐶 (𝑡𝑡 = 𝜏𝜏)
(4)
2. In the circuit given in figure 1 below, after some time the switch moves
to the position as indicated at time 𝑡𝑡 = 0. Given that 𝑅𝑅 = 3𝑘𝑘Ω, 𝐿𝐿 =
2 𝑚𝑚𝑚𝑚, answer the following:
FIGURE 1
2.2.1
Write an expression for 𝐼𝐼𝐿𝐿 (𝑡𝑡), given that the initial current is 1.5A
2.2.2 What is the final current through inductor – i.e. 𝐼𝐼𝐿𝐿 (𝑡𝑡 = ∞)
2.2.3
Calculate the current at the time constant – i.e. 𝐼𝐼𝐿𝐿 (𝑡𝑡 = 𝜏𝜏)
(4)
(2)
(4)
3. In order to conduct transient analysis of circuits with capacitance and inductance, important
assumptions are made regarding voltage and current. Answer the following:
3.1
3.2
𝑣𝑣(0− ) =? and 𝑖𝑖(0− ) =?
What do these assumptions actually mean?
(2)
(2)