Ohm's Law

Ohm’s Law

  • Ohm’s Law states that the current flowing in a circuit is directly proportional to the potential difference (or voltage) across the component, provided the temperature remains constant.
  • This means if you double the voltage, the current will also double.
  • Ohm’s Law can be written as V = IR, where V is voltage, I is current, and R is resistance.
  • This equation is a simple way to represent the relationship between voltage, current, and resistance.

Resistance

  • Resistance is a measure of how much a component reduces the electric current flowing through it.
  • The unit of resistance is the ohm (Ω).
  • A higher resistance leads to a lower current for a given voltage, according to Ohm’s Law.
  • Resistance in a circuit can be increased by adding more components, thus increasing the total resistance.

Current

  • Current is the flow of electric charge through a conductor.
  • It is measured in amperes (A) and can be calculated by dividing the voltage by the resistance (I = V/R).
  • The larger the potential difference across a component, the larger the current that flows through it, given that the resistance is constant.

Voltage

  • Voltage, or potential difference, is the energy per unit charge. It is what pushes the current around the circuit.
  • It is measured in volts (V) and can be calculated by multiplying current by resistance (V = IR).
  • The larger the voltage, the larger the current, given that the resistance is constant.

Understanding Ohm’s Law

  • Graphs can be drawn to show the relationship between current and voltage for a particular component.
  • For an ohmic conductor (e.g., a resistor at a constant temperature), the graph is a straight line through the origin. This is because the current is directly proportional to the voltage (as shown by Ohm’s Law). Hence, the resistance is constant.
  • For a non-ohmic conductor (e.g., a filament bulb), the graph is a curve. This is because the resistance of the bulb increases as the filament gets hotter, which deviates from Ohm’s Law.
  • Understanding and applying Ohm’s Law is crucial when working with electrical circuits, as it allows us to calculate values for voltage, current, and resistance and predict how changes in one will affect the others.