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Introduction to AC (in Hindi)
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What is an alternating current? and construction of an AC generator

Udit Gupta is teaching live on Unacademy Plus

Udit Gupta
A Mechanical Engineer from NIT Allahabad here to help learners with physics. Also a Star ⭐ educator.

Unacademy user
Thanks sir for sharing this course. you're awesome. it is so helpful
Please sir problems bhi karayiye please it's a request. Thank you
Sir,we can represent S.H.M. as a function both sin as well as cos, can we do the same for A.C. also?? if yes,then what name is given to the cos curve(as sinusoidal name is given for the sin curve)
Udit Gupta
10 months ago
see cos is also a sine wave with a phase difference of pi by 2. You may call it cosusoidal wave for your own prefernece but it is still known as sinusoidal wave. The same could not be said for tan or cot.
Udit Gupta
10 months ago
SHM can also be represented as cos or sin function
Bhawna Bhatt
10 months ago
thanks sir, Now I got it😊

  2. WELCOME I am your educator, Udit Gupta Today I bring forward one of the most easiest to score topic and introduce it slightly to get a grasp of the topic. In this lesson we will get acquainted with AC current and how an AC generator works. For more lessons and courses, visit the following link:

  3. WHAT IS ALTERNATING CURRENT? A current is established in the circuit, when a resistor is connected across the terminals of a battery. This current has a unique direction, and moves via the external resistor from the +ve terminal to the -ve terminal. The magnitude of this current is almost constant. If the direction of the current in a resistor or in any other element changes alternately, the current is called an alternating current.

  4. GRAPHICAL REPRESENTATION In this course, we shall study the alternating current (AC) that varies sinusoidally with time. Such a current is given by: alternating Time

  5. EXPLANATION The current repeats its value after each time interval T 2n/ . This time interval is called the time period. . The current is +ve for half the time period and is-ve for the remaining half period This implies, its direction reverses after each half time period The maximum value of the current io which is called the peak current or the current amplitude

  6. EXPLANATION . To get sinusoidally varying alternating current, we need a source which can generate sinusoidally varying emf. . An AC generator, also called and AC dynamo, can be used as such a source. It converts mechanical energy into electrical energy, producing an alternating emf and hence an alternating current

  7. AC GENERATOR - CONSTRUCTION Magnet The diagram shows us three main parts of the dynamo: > Magnets > Slip rings Brushes Brus Slip-Rings Magnet: It could be a permanent or an electromagnet. The poles of magnet face each other so that a strong magnetic field is produced between the poles.

  8. AC GENERATOR - CONSTRUCTION Armature: It is a coil generally wound over a soft-iron core. The core increases the magnetic field due to its magnetization. The two ends of the coil are connected to two slip rings. The coil together with the rings can rotate in the magnetic field. The axis of rotation is in the plane of the coil but perpendicular to the magnetic field. Brushes: Two graphite brushes permanently touch the slip rings. As the armature rotates, the slip rings slip against the brushes so that the contact is maintained all the time. These brushes are connected to two terminals. The external circuit is connected to these terminals.

  9. THANKS FOR WATCHING! If you think this was genuine stuff and could benefit others do not forget to rate & review this course Doubts and queries are welcome. Comment or leave a message to get it sorted. For more such courses, visit:

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