# AC voltage, DC voltage, AC current and DC current

1. Apr 28, 2012

### rama1001

Hi,
I know that existence of AC and DC currents but what exactly the same with AC and DC potential difference. Of-course it was very basic question and i apologize if it annoys any. Please explain the difference only in terms of voltage.

Thank you.

2. Apr 28, 2012

### phinds

AC is normally the result of an alternating voltage and DC is the result of a constant voltage. One does not normally speak of "an AC potential difference".

3. Apr 28, 2012

### rama1001

How the Voltage alternates practically? You mean changing the volatge over and over like 12v, 15v, 18v,7v and so on when the load is on.

4. Apr 28, 2012

### phinds

NO, I mean using an alternating source. You really should look up AC generators.

5. Apr 28, 2012

### jim hardy

often it's good to look up the verb in an unfamiliar phrase.

ALTERNATING means it's switching direction at regular interval, just as [STRIKE]a pendulum[/STRIKE] (oops - clocks are digital nowadays so make that ) a child on a swing.

So the voltage varies in time typically going smoothly from zero to some positive value, then to equal negative value, then back to zero and so on.

In US, power at your wall socket makes sixty such cycles every second. Much of rest of worls is 50 cycles. Those poor folks in Japan have my sympathy - part of their country is 50 and part 60.

6. Apr 28, 2012

### Bobbywhy

rama1001, After some searching I found this simple “tutorial”, or “teach yourself” to help you get a grasp of Electricity:

“This tutorial is a brief introduction to the concepts of charge, voltage, and current. This tutorial is not as long and tedious as a college textbook, yet it contains more information than students are likely to find in an elementary schoolbook.”
http://www.swansontec.com/set.html

I first learned electronics in Navy schools, so I am a little biased. So, if someone is serious about learning electricity and electronics, this free downloadable book is the best choice possible!
“Here is the "Electricity - Basic Navy Training Courses" (NAVPERS 10622) in its entirety (or will be eventually). It should provide one of the Internet's best resources for people seeking a basic electricity course - complete with examples worked out (links to quizzes at end of chapters).
Electricity - Basic Navy Training Courses
NAVPERS 10622
PREFACE
This book is intended as a basic reference for all enlisted men of the Navy whose duties require them to have a knowledge of the fundamentals of electricity.”
http://www.rfcafe.com/references/electrical/Electricity%20-%20Basic%20Navy%20Training%20Courses/electricity%20-%20basic%20navy%20training%20courses.htm [Broken]

Last edited by a moderator: May 5, 2017
7. Apr 28, 2012

### jim hardy

Good for you BobbyW !!!

1960's and 70's Navy training was excellent. It produced exreemely competent people.

8. Apr 28, 2012

### Bobbywhy

Thx, Old Jim!

AFU-A (32 weeks) and AQF (12 weeks) at NATTC, Memphis, 1961

After the USN, jobs were plentiful. I was especially welcomed everywhere because of that training!

Cheers, Bobbywhy