Time constant in inductors, Physics

Time constant in Inductors:

It is impossible to decide exactly when the maximum point is reached on an exponential curve, or when the curve has fallen to exactly zero.   To enable calculations to be performed a  time constant is used. The time constant gives an indication of the time taken for the current to rise to its maximum value or fall to zero. The time constant is defined as either:

  • The time taken for a current to reach its maximum value if the initial rate of increase were maintained.
  • The time taken for the current to reach 0.632 of its maximum value (or 63.2%).

The latter definition arises since it is found that after one time constant, the current has always built up to 63.2% of its maximum value.  The time constant for a series LR circuit is given by:

          Time Constant  = L/R seconds

Therefore, although it is not possible to say exactly when the current reaches its maximum value, for all practical purpose it can be considered a maximum after 5 time constants:

          Maximum Current flows after 5L/R

 

 

Posted Date: 9/13/2012 6:28:09 AM | Location : United States







Related Discussions:- Time constant in inductors, Assignment Help, Ask Question on Time constant in inductors, Get Answer, Expert's Help, Time constant in inductors Discussions

Write discussion on Time constant in inductors
Your posts are moderated
Related Questions
Q. As-per to Coulombs Law if two charged particles are repelled with a given force at a distance d by what multiple will the force decrease by if d is increased by 4 times? An

Q. A small pin fixed on a table top is viewed from above from a distance of 50 cm. By what distance would the pin appear to be raised if it is viewed from the same point through a

99 ml of H 2 O is initially at room temperature (20.0 o C). A chilled steel rod at 2.0 o C is placed in the water. If the final temperature of the system is 18.7 o C, what is th

In an ideal transformer , the no. of turns in primary & secondary are 200 & 1000 respectively .If power input to primary is 10kW at 200V.Calculate i)output voltage ii)current in

Q. Describe diffrent principle of rays? Principle Ray I : The easy one it hits the lens smack dab in the middle as well as passes straight on through. Principle Ray II : P

A wheel is mounted on a stationary axle starts at rest and is given the following angular acceleration a =(9-12t) (SI units)where t is the time after the wheel begins to rotate.Fin

Question 1. Explain the picture-archiving system used in diagnostic imaging departments. 2. Discuss the role of Medical Imaging Informatics in modern radiology departments.

Graphing Motion - Position, Velocity and Acceleration With graphing and/or the advent of calculus, not only can we calculate the average values like those calculated above, but

A person is tasked with creating a ray diagram to resolve the characteristics of the image of an object formed by a concave lens. The person has accurately drawn the principal axis

It's working is based on the detail that if a beam of electron is subjected to the crossed electric field   and magnetic field , it experiences a force because of each field. In ca