Transients in R-L-C Circuits
Task 1 – Learning Outcomes 4.1 and 4.2
Use Laplace transforms for the transient analysis of networks
Calculate circuit responses to a step input in practical situations
1. A DC supply of 10V is applied to the circuit shown below. Assume zero conditions when the switch is closed. Use Laplace Transforms to calculate:

a. The current flowing in the circuit in the T and S domains

b. The voltage across the inductor in the T and S domains

c. The voltage across the capacitor in the T and S domains

2. The field coil of a D.C. motor is shunted by a 200O arc-quenching resistor as shown below, determine:

a. An expression for the current in the field coil at time t seconds after connection to the 200V supply

b. The total current taken by the parallel components 0.5 seconds after switching on

c. The peak voltage VAB at the instant the supply is switched off (assuming steady state conditions have been achieved before switching off)

d. The time taken for the coil current to fall to 10% of its normal running value after the supply is switched off (assuming steady state conditions have been achieved before switching off)