What Is Voltage? Definition
Voltage (or potential difference) is the energy required to move a unit charge from one place to another place.
Let, dw work is done to move dq charge from a to b. Then voltage between a and b, Vab or simply V can be expressed:
Vab = dw/dq
Here,
Unit of energy dw is Joule (J).
Unit of charge dq is coulomb (C)
So, unit of voltage is Joule per coulomb, J/C. This is called volt.
Voltage Polarity - Positive and Negative Point
The Positive (+) and negative (-) signs defines the voltage polarity. The following figure shows voltage vab across and element (this may be resistor, capacitor or battery) between a and b. Here a is positive and b is negative, and it’s value is vab. This means that voltage at positive point a is vab value higher than negative point b.
For example, the following both figures 1 and 2 represents the same voltage.
In figure 1,
we see that point a is positive and point b is negative and voltage is ( V. So, voltage at point a is 9 V higher than voltage b.
On the second figure,
Point a is negative and point b is positive and voltage is -9 V. So voltage at point b is -9 V higher than point a. In other words, Vb-Va= -9, Or, Va-Vb=9. So, voltage at point a is 9 V higher than voltage at point b. Which is same as figure 1.
Types of Voltage: AC and DC
There are two types of voltage one is DC voltage and the other one is AC voltage.
DC voltage: The voltage which value is constant with time and never change its polarity is called DC voltage.
AC voltage: This voltage changes polarity with time.
Frequently Asked Questions
What is voltage?
Voltage is defined as the energy required to move an unique charge through e conductor.
What is the unit of voltage?
SI unit of voltage is volt (V). 1 V = 1 J/C.
What is the name of voltage measurement device?
The voltage measurement device is called voltmeter.
What are the types of voltage?
There are two types of voltage: AC and DC voltage
This is a simple discussion about voltage. In future posts, we will discuss about it’s calculation and application. Thank You!
