Voltage Divider

Definition

A voltage divider is a simple circuit that reduces an input voltage to a lower output voltage by using a combination of resistors. It is a fundamental concept in electrical engineering and is widely used in electronic circuits to provide a desired voltage level.

5 Must Know Facts For Your Next Test

1. The output voltage of a voltage divider is directly proportional to the ratio of the two resistor values.
2. Voltage dividers are commonly used to provide a reference voltage for electronic circuits, such as in sensor applications or biasing circuits.
3. The formula for the output voltage of a voltage divider is $V_{out} = V_{in} \cdot \frac{R_2}{R_1 + R_2}$, where $R_1$ and $R_2$ are the resistor values.
4. Voltage dividers can be used to adjust the level of a signal, such as reducing the voltage from a power supply to a level suitable for a microcontroller or other electronic component.
5. The input impedance of a voltage divider is the parallel combination of the two resistor values, which can be important in circuit design to avoid loading effects.

Review Questions

• Explain how the resistor values in a voltage divider circuit determine the output voltage.
  • The output voltage of a voltage divider is directly proportional to the ratio of the two resistor values. Specifically, the output voltage $V_{out}$ is given by the formula $V_{out} = V_{in} \cdot \frac{R_2}{R_1 + R_2}$, where $V_{in}$ is the input voltage, $R_1$ and $R_2$ are the resistor values. By adjusting the resistor values, the output voltage can be tuned to a desired level, making voltage dividers useful for providing reference voltages or adjusting signal levels in electronic circuits.
• Describe how a voltage divider circuit relates to the concept of resistance and Ohm's Law.
  • Voltage dividers are closely related to the concept of resistance and Ohm's Law. Ohm's Law states that the voltage across a resistor is equal to the current through the resistor multiplied by the resistance, or $V = IR$. In a voltage divider, the input voltage is divided across the two resistors based on their relative resistance values, as described by the voltage divider formula. This relationship between voltage, current, and resistance is fundamental to understanding how voltage dividers function and how they can be used to control voltage levels in electronic circuits.
• Evaluate the importance of voltage dividers in the context of resistivity and resistance, and explain how they can be used to measure or adjust resistance in a circuit.
  • Voltage dividers are crucial in the context of resistivity and resistance because they allow for the measurement and adjustment of resistance values in electronic circuits. By using a voltage divider to measure the voltage drop across a resistor, the resistance can be calculated using Ohm's Law. Additionally, voltage dividers can be used to adjust the resistance in a circuit, which can be important for tasks such as biasing transistors, setting reference voltages, or controlling the level of a signal. The ability to precisely control and measure resistance through voltage dividers is a fundamental aspect of their utility in electrical engineering and circuit design, particularly in the context of understanding and applying the concepts of resistivity and resistance.

Related terms

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

Ohm's Law: The relationship between voltage, current, and resistance in an electrical circuit, expressed as V = IR.

Potential Difference: The difference in electric potential between two points in a circuit, which drives the flow of electric current.