What is a Voltage Divider?

Introduction

A voltage divider, also known as a voltage splitter, is an electrical circuit or arrangement of components used to divide or reduce a voltage into two or more smaller voltages.

It is a simple passive circuit that consists of resistors connected in series, and it’s commonly used in electronics for various purposes, including signal conditioning, level shifting, and voltage measurement.

How does a voltage divider work?

The basic principle of a voltage splitter is based on Ohm’s Law, which states that the current (I) flowing through a resistor is directly proportional to the voltage (V) across it and inversely proportional to the resistance (R). In a voltage splitter, two resistors are typically used in series, and the voltage across one of the resistors is taken as the output voltage.

The most common application of a voltage splitter is to reduce a higher voltage to a lower voltage.

The output voltage (Vout) can be calculated using the following formula, where R1 and R2 are the resistance values of the two resistors:

Vout = Vin * (R2 / (R1 + R2))

In this equation:

  • Vin is the input voltage that you want to divide.
  • R1 is the resistance of the first resistor in the series.
  • R2 is the resistance of the second resistor in the series.

Voltage Divider Calculator

By choosing appropriate resistor values for R1 and R2, you can determine the desired output voltage. Voltage dividers are commonly used for tasks like:

  1. Level Shifting: Converting a high-level signal to a lower level suitable for input to a microcontroller or other logic devices.
  2. Voltage Scaling: Reducing the voltage of a signal to match the input range of an analog-to-digital converter (ADC).
  3. Sensor Interface: Interfacing with sensors that produce a voltage proportional to some physical quantity (e.g., temperature, light intensity).
  4. Biasing and Reference Voltage Generation: Creating a stable reference voltage for other components in a circuit.
  5. Attenuation: Reducing the amplitude of a signal while maintaining its shape. Note that a T-attenuator incorporates a voltage divider.

Summary

It’s important to choose resistor values carefully to ensure that the voltage division ratio is accurate and that the resistors can handle the power dissipated in the circuit without overheating or affecting the signal quality. Additionally, consider the tolerance of the resistors when designing voltage dividers to achieve the desired precision in your application.

Notes