Ohms Law-Voltage, Current, Resistance:
What is Voltage?
The voltage between two points is equal to the electrical potential difference between those points. It is actually the electromotive force (emf), responsible for the movement of electrons (electric current) through a circuit. A flow of electrons forced into motion by voltage is current. Voltage represents the potential for each Coulomb of electric charge to do work. It is represented by Letter V.
What is Current?
Current is the rate at which electric charge flows past a point in a circuit. In other words, current is the rate of flow of electric charge. It is represented by Letter I.
Current is the effect (voltage being the cause). Current cannot flow without Voltage. No current flows if no load is connected. Current flowing in the circuit is measured by Ammeter.
What is Electrical Circuit?
An electric circuit is a path in which electrons from a voltage or current source flow. The point where those electrons enter an electrical circuit is called the “source” of electrons. The point where the electrons leave an electrical circuit is called the “return” or “earth ground”
What is Resistor and Resistance?
A resistor is an electrical component that limits or regulates the flow of electrical current in an electronic circuit. Resistors can also be used to provide a specific voltage for an active device such as a transistor. Resister is represented by letter R and its unit is OHM.
Symbol of Resistor:
The power of resistor is presented in OHM. More the OHM more AMP it limits. Although voltage always pushes AMPS to flow forward. So we understood that there is special relationship between these. The special relation is called OHMs law.
OHMs law is the basic.
Solution: From Ohm’s formula, I = V/R = 5 V / 10 Ω = 0.5 A
Example-1: A potential difference of 10 volts is applied to 10 Ω resistor (Since resistor is constant). Find the current passing through it.
Solution: I = V/R = 10 V / 10 Ω = 1 A
By comparing above cases one can understand that for a constant resistance (10 Ω) the amount of current increases when we increase the voltage.
Now, for a constant voltage, statement will become: I = V/R → I ∝ 1/R
The current is inversely proportional to the connected resistor. The two examples below better illustrate the above statement.
Example-2: A voltage source of 5 V connects to a 10 Ω resistor, find the current flowing through it.
Solution: From formula, I = V/R = 5 V / 10 Ω = 0.5 A.
From above example, one can understand that by increasing Resistance the current decreases.