Electrical Transients

A capacitor of 100 micro farad is connected in series with a resistance of 1000 ohms. The time constant of the circuit is

A coil has a resistance of 5 ohms and inductance of 1 H. At t = 0 it is connected to a 2 V battery. Find the rate of rise of current when i = 0.2 ampere.

Calculate the time taken by the capacitor of 1 μF and in series with a 1 MΩ resistance to be charged up to 80% of the final value.

A series RL circuit is connected across a dc source through a switch. Three milliseconds after the switch is closed, the voltage across the inductance is 20 V, and it drops to 5 V after 25 ms. If R = 100 ohms, find L. Assume at t = 0, i = 0.

A 100 μF capacitor initially charged to 24 V is discharged across a series combination of a 1 kΩ resistor and a 200 μF capacitor. Find the current after 1 sec.

An inductance of 40 mH is connected in series with 300 ohms resistance, At t=0, the energy stored is 0.96 microjoule. Find the current at t=0.

A coil of inductance 10 H and resistance 2 ohms is supplied at 20 v, Find the average emf induced when the circuit is opened if the current fails to zero in 0.5sec.

A 2 μF capacitor with an initial charge of 100 μC is connected across a 100 Ω resistor at t = 0. Calculate the time in which the transient voltage across the resistor drops from 40 to 10 volts.

A time of 10 milliseconds is required for the current on a series RL dc circuit to reach 90% of its final steady state value. What is the time constant in seconds for the circuit?

A 1.5 MΩ resistor is connected in series with a 20 μF capacitor. The voltage source is 120 volts dc. Determine the current at t = 10 seconds after the switch is closed.

A capacitor is charged by a dc source through a resistor of one megohm. If in one second, the potential difference across capacitor reaches 80% of its final value, calculate its capacitance.

A capacitor of 40 μF capacitance in series with 2,000 ohms is suddenly connected across a 200-volt source. What is the energy stored in the capacitor after 0.04 sec?

A current of 20 A is flowing in an RL series circuit the instant before the switch is opened. If R = 10 Ω and L = 10 H, find the current after 3 seconds have elapsed.

The current in a coil decays as follows: when t = 0.002 s the current is 10 mA; when t = 0.006 s the current drops to 4 mA. The time constant of the coil is _______.

A capacitor of 0.1 μF capacitance is charged to a potential difference between plates of 100 V and is discharged through a resistor of 1 megohm. Calculate the initial rate of decay of the capacitor voltage.

A 1.5 MΩ resistor is connected in series with a 20 μF capacitor. The voltage source is 120 volts dc. Determine the time at which the voltage across the capacitor is 75% of the source voltage.

The field circuit of a 4-pole dc generator has a resistance of 200 Ω and an inductance of 100 H. If it is connected to a 400 V supply, find the time taken for the current to reach 1.5 A.

A 60 μF capacitor is connected in series with a 40,000 Ω resistor. If the capacitor is initially uncharged, determine the resistor voltage when t = 1.5 time constants for a suddenly applied source emf of 120 volts.

A coil having a resistance of 10 Ω and an inductance of 4 H is switched across a 20 V dc source. Calculate the rate of current change when the current reaches 50% of its final steady value.