Ohm's Law And Resistors - SS3 Physics Lesson Note

Ohm's law is a fundamental principle in electronics that relates the current flowing through a conductor to the voltage applied across it and the resistance of the conductor. It states that the current (I) through a conductor is directly proportional to the voltage (V) applied across it, and inversely proportional to the resistance (R) of the conductor:

 

I = VR

This equation can also be rearranged to solve for voltage or resistance:

V = I×R

R =VI

The unit of resistance is the ohm (Ω), named after Georg Simon Ohm, the German physicist who first formulated the law.

Resistors are electronic components that are designed to provide a specific amount of resistance in a circuit. They can be used to control the amount of current flowing through a circuit or to limit the amount of voltage that reaches a particular component.

Resistors are typically made of a material that is highly resistant to the flow of electric currents, such as carbon or metal. The resistance of a resistor is determined by its physical characteristics, such as its length, cross-sectional area, and material properties. Resistors are available in a range of values, from fractions of an ohm to millions of ohms.

In a circuit, resistors are connected in series or parallel to achieve the desired resistance. When resistors are connected in series, the total resistance is equal to the sum of the individual resistances. When resistors are connected in parallel, the total resistance is less than the resistance of any individual resistor.

Resistors have many practical applications in electronics, such as in voltage dividers, current limiters, and filters. They are also used in many electronic devices, such as computers, televisions, and mobile phones.