Sunday, February 05, 2023
08:00 PM (GMT +5)

Go Back   CSS Forums > CSS Compulsory Subjects > General Science & Ability

Reply Share Thread: Submit Thread to Facebook Facebook     Submit Thread to Twitter Twitter     Submit Thread to Google+ Google+    
 
LinkBack Thread Tools Search this Thread
  #1  
Old Thursday, July 02, 2020
Banned
 
Join Date: Feb 2020
Location: Lahore
Posts: 22
Thanks: 8
Thanked 4 Times in 4 Posts
Aleeha Sheikh is on a distinguished road
Post

Electricity flows in two ways: either in an alternating current (AC) or in a direct current (DC). Electricity or "current" is nothing but the movement of electrons through a conductor, like a wire. The difference between AC and DC lies in the direction in which the electrons flow. In DC, the electrons flow steadily in a single direction, or "forward." In AC, electrons keep switching directions, sometimes going "forward" and then going "backward."
Alternating current is the best way to transmit electricity over large distances.

Comparison:

1. Amount of energy that can be carried

Alternating Current: Safe to transfer over longer city distances and can provide more power.
Direct Current: Voltage of DC cannot travel very far until it begins to lose energy.

2. Cause of the direction of flow of electrons

Alternating Current: Rotating magnet along the wire.
Direct Current: Steady magnetism along the wire.

3. Frequency

Alternating Current: The frequency of alternating current is 50Hz or 60Hz depending upon the country.
Direct Current: The frequency of direct current is zero.

4. Direction

Alternating Current: It reverses its direction while flowing in a circuit.
Direct Current: It flows in one direction in the circuit.

5. Current

Alternating Current: It is the current of magnitude varying with time.
Direct Current: It is the current of constant magnitude.

6. Flow of Electrons

Alternating Current: Electrons keep switching directions - forward and backward.
Direct Current: Electrons move steadily in one direction or 'forward'.

7. Obtained from

Alternating Current: A.C Generator and mains.
Direct Current: Cell or Battery.

8. Passive Parameters

Alternating Current: Impedance.
Direct Current: Resistance only.

9. Power Factor

Alternating Current: Lies between 0 & 1.
Direct Current: It is always 1.

10. Types

Alternating Current: Sinusoidal, Trapezoidal, Triangular, Square.
Direct Current: Pure and pulsating.

Origins of AC and DC current

A magnetic field near a wire causes electrons to flow in a single direction along the wire, because they are repelled by the negative side of a magnet and attracted toward the positive side. This is how DC power from a battery was born, primarily attributed to Thomas Edison's work.
AC generators gradually replaced Edison's DC battery system because AC is safer to transfer over the longer city distances and can provide more power. Instead of applying the magnetism along the wire steadily, scientist Nikola Tesla used a rotating magnet. When the magnet was oriented in one direction, the electrons flowed towards the positive, but when the magnet's orientation was flipped, the electrons turned as well.

Use of transformers with Alternating Current

Another difference between AC and DC involves the amount of energy it can carry. Each battery is designed to produce only one voltage, and that voltage of DC cannot travel very far until it begins to lose energy. But AC's voltage from a generator, in a power plant, can be bumped up or down in strength by another mechanism called a transformer. Transformers are located on the electrical pole on the street, not at the power plant. They change very high voltage into a lower voltage appropriate for your home appliances, like lamps and refrigerators.

Storage and Conversion From AC to DC and Vice Versa

AC can even be changed to DC by an adapter that you might use to power the battery on your laptop. DC can be "bumped" up or down, it is just a little more difficult. Inverters change DC to AC. For example, for your car an inverter would change the 12 volt DC to 120 Volt AC to run a small device. While DC can be stored in batteries, you cannot store AC.
Reply With Quote
The Following User Says Thank You to Aleeha Sheikh For This Useful Post:
awaz (Friday, April 08, 2022)
Reply

Tags
ac current, dc current

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
current affairs 2019 ppsc fpsc Abuzarkandwal PPSC Others Examinations 0 Wednesday, September 04, 2019 07:24 PM
I Need Mcqs for Economics Beauty Economics 24 Tuesday, February 28, 2017 12:20 AM
CURRENT AFFAIRS;Taming the monster--My humble tips Hamza Salick Current Affairs 23 Saturday, August 31, 2013 12:50 AM
basic electronics short questions ravaila Physics 0 Monday, February 22, 2010 05:14 PM
All about Current Affairs Argus Current Affairs 1 Tuesday, November 15, 2005 04:01 PM


CSS Forum on Facebook Follow CSS Forum on Twitter

Disclaimer: All messages made available as part of this discussion group (including any bulletin boards and chat rooms) and any opinions, advice, statements or other information contained in any messages posted or transmitted by any third party are the responsibility of the author of that message and not of CSSForum.com.pk (unless CSSForum.com.pk is specifically identified as the author of the message). The fact that a particular message is posted on or transmitted using this web site does not mean that CSSForum has endorsed that message in any way or verified the accuracy, completeness or usefulness of any message. We encourage visitors to the forum to report any objectionable message in site feedback. This forum is not monitored 24/7.

Sponsors: ArgusVision   vBulletin, Copyright ©2000 - 2023, Jelsoft Enterprises Ltd.