Voltage Divider

Definition

A voltage divider is a simple circuit that produces an output voltage that is a fraction of its input voltage. It is a fundamental concept in electrical engineering and is commonly used to reduce or adjust voltage levels in various electronic circuits.

5 Must Know Facts For Your Next Test

1. The output voltage of a voltage divider is determined by the ratio of the resistor values in the circuit.
2. Voltage dividers are commonly used to provide a lower voltage signal from a higher voltage source, such as in sensor circuits or biasing circuits.
3. The input voltage is divided between the resistors in proportion to their resistance values, following the principles of series resistance.
4. Voltage dividers can be used to adjust the voltage level in a circuit without significantly loading the input source.
5. The voltage division principle applies to both series and parallel resistor configurations, as long as the resistors are connected in a specific arrangement.

Review Questions

• Explain how the resistance values of the resistors in a voltage divider circuit determine the output voltage.
  • The output voltage of a voltage divider is determined by the ratio of the resistor values. Specifically, the output voltage is equal to the input voltage multiplied by the ratio of the smaller resistor value to the total resistance of the divider. This relationship is governed by the principles of series resistance, where the voltage drop across each resistor is proportional to its resistance value. By selecting appropriate resistor values, the desired output voltage can be obtained from the input voltage.
• Describe how a voltage divider can be used to adjust the voltage level in a circuit without significantly loading the input source.
  • A voltage divider can be used to adjust the voltage level in a circuit without significantly loading the input source because it presents a high impedance to the input. The voltage divider circuit effectively acts as a buffer, allowing a portion of the input voltage to be tapped off without drawing a large amount of current from the source. This is particularly useful in situations where the input source has a limited current-sourcing capability, and the load on the voltage divider is relatively high impedance. By carefully selecting the resistor values, the voltage divider can provide the desired output voltage while minimizing the impact on the input source.
• Analyze how the voltage division principle applies to both series and parallel resistor configurations, and explain the key differences in the voltage distribution between these two scenarios.
  • The voltage division principle applies to both series and parallel resistor configurations, but the way the voltage is distributed across the resistors differs. In a series resistor configuration, the voltage is divided across the individual resistors in proportion to their resistance values, following Ohm's law. The current is the same through all the resistors, and the voltage drops across each resistor are additive. In a parallel resistor configuration, the voltage is the same across all the resistors, but the current is divided among the parallel branches based on their relative resistance values. The total resistance of the parallel network affects the overall voltage division, as the parallel resistance determines the fraction of the input voltage that appears across each resistor. Understanding these differences is crucial for correctly applying the voltage division principle in various circuit designs.

Related terms

Series Resistance: The total resistance in a series circuit, which determines the division of voltage between the components.

Parallel Resistance: The combined resistance of multiple resistors connected in parallel, which affects the voltage distribution in a circuit.

Ohm's Law: The fundamental relationship between voltage, current, and resistance in an electrical circuit, which is crucial for understanding voltage dividers.