I = v/r

Definition

The equation $$i = \frac{v}{r}$$ defines the relationship between electric current (i), voltage (v), and resistance (r) in a circuit. This fundamental formula illustrates how current flows through a conductor when a voltage is applied, inversely proportional to the resistance encountered. Understanding this relationship is crucial for analyzing and designing electrical circuits, as it helps predict how changes in voltage or resistance will affect the current flow.

5 Must Know Facts For Your Next Test

1. Ohm's law states that for a given circuit at a constant temperature, the current is directly proportional to the voltage and inversely proportional to the resistance.
2. In this equation, if the resistance increases while the voltage remains constant, the current will decrease.
3. Conversely, if the voltage increases while resistance stays the same, the current will increase.
4. This relationship is essential for understanding how electrical components behave under different conditions and is foundational in circuit analysis.
5. Ohm's law can be applied in both direct current (DC) and alternating current (AC) circuits, although AC circuits may involve more complex factors like impedance.

Review Questions

• How does changing the voltage in a circuit affect the current according to the equation $$i = \frac{v}{r}$$?
  • According to the equation $$i = \frac{v}{r}$$, if you increase the voltage while keeping the resistance constant, the current will also increase proportionally. This means that with a higher voltage applied across a resistor, more charge carriers are driven through it, resulting in a greater current. Conversely, decreasing the voltage will reduce the current in the same way.
• What implications does Ohm's law have for designing electrical circuits when selecting components like resistors and power supplies?
  • When designing electrical circuits, Ohm's law guides engineers in choosing appropriate components by allowing them to calculate how much current will flow for a given voltage and resistance. By knowing these values, they can select resistors that limit current to safe levels and choose power supplies that provide adequate voltage without exceeding component ratings. This careful selection is crucial to ensure circuit functionality and safety.
• Evaluate how understanding $$i = \frac{v}{r}$$ can impact troubleshooting in electrical systems.
  • Understanding $$i = \frac{v}{r}$$ significantly impacts troubleshooting because it provides a systematic approach to diagnosing issues within electrical systems. By measuring voltage and resistance at various points in a circuit, one can use this equation to calculate expected current values. Deviations from these expected values can indicate problems such as short circuits or faulty components, enabling technicians to quickly identify and resolve issues to restore proper functionality.

Related terms

Electric Current: The flow of electric charge through a conductor, measured in amperes (A).

Voltage:

The electric potential difference between two points in a circuit, measured in volts (V).

Resistance:

The opposition to the flow of electric current, measured in ohms (Ω).