Ohm's law is a fundamental principle in electrical circuits that describes the relationship between voltage, current, and resistance. It was formulated by the German physicist Georg Simon Ohm in the 19th century and remains a cornerstone in electrical engineering and electronics.
Ohm's law can be expressed mathematically as:
V = I * R
Where:
V is the voltage across a circuit element (measured in volts, V).
I is the current flowing through the circuit element (measured in amperes, A).
R is the resistance of the circuit element (measured in ohms, Ω).
In simple terms, Ohm's law states that the voltage across a circuit element is directly proportional to the current flowing through it, with the proportionality constant being the resistance of the element.
Key points to understand about Ohm's law:
Voltage (V): Voltage represents the electrical potential difference between two points in a circuit. It is the driving force that causes current to flow. In most circuits, voltage is provided by a power source such as a battery or power supply.
Current (I): Current is the flow of electric charge through a circuit. It is the rate at which charges move through a conductor. Current flows from the positive terminal of the voltage source to the negative terminal in a closed circuit.
Resistance (R): Resistance is the property of a circuit element that opposes the flow of current. It determines how much the current will be limited in a circuit. The higher the resistance, the lower the current for a given voltage.
Proportional relationship: According to Ohm's law, when the resistance remains constant, the voltage and current in a circuit are directly proportional. If you increase the voltage, the current will increase proportionally, and vice versa.
Mathematically, you can also rearrange Ohm's law to solve for other variables:
I = V / R: This formula allows you to calculate the current (I) in a circuit if you know the voltage (V) and resistance (R).
R = V / I: This formula lets you find the resistance (R) of a circuit element if you know the voltage (V) and current (I) passing through it.
Ohm's law provides a crucial foundation for understanding and analyzing electrical circuits, making it easier to design and troubleshoot various electronic devices and systems.