Voltage divider

Impedance voltage divider

Resistive divider2

RC Divider

HighVoltageDividerProbe

Voltage Divider is a fundamental concept in electrical engineering and electronics that involves dividing the voltage across a circuit. The principle of the voltage divider is used to reduce a high voltage to a lower one, based on the ratio of two resistors placed in series within a circuit. This concept is critical in designing electronic circuits, especially in creating adjustable voltage supplies, measuring signals, and interfacing sensors with microcontrollers.

Principle

The basic principle of a voltage divider is derived from Ohm's Law and the series circuit rules. In a series circuit, the current flowing through each component is the same, but the voltage across each component can vary depending on its resistance. The voltage divider consists of two resistors, \(R_1\) and \(R_2\), connected in series across a voltage supply, \(V_{in}\). The output voltage, \(V_{out}\), is taken across \(R_2\). According to Ohm's Law, the voltage across \(R_2\) is given by:

\[V_{out} = V_{in} \times \frac{R_2}{R_1 + R_2}\]

This equation shows that \(V_{out}\) is a fraction of \(V_{in}\), determined by the ratio of \(R_2\) to the total resistance (\(R_1 + R_2\)).

Applications

Voltage dividers have a wide range of applications in electronic circuits:

• Voltage Scaling: To scale down a high voltage to a lower level that is safe for microcontrollers and other sensitive electronic devices.
• Sensor Interface: To interface sensors with analog outputs to digital measurement systems, adjusting the sensor output voltage to the input range of the Analog-to-Digital Converter (ADC).
• Signal Conditioning: To adjust signal levels to match the requirements of the next stage in a signal processing chain.
• Impedance Matching: To match the impedance between different parts of an electronic system to maximize power transfer or minimize signal reflection.

Limitations

While voltage dividers are simple and useful, they have limitations:

• Power Efficiency: They are not power efficient for reducing high voltages to low voltages at significant current levels, as the excess power is dissipated as heat in the resistors.
• Load Effect: The output voltage can vary significantly with changes in the load connected to the divider, making them unsuitable for applications requiring a stable voltage under varying load conditions.

Types of Voltage Dividers

Besides the basic resistive voltage divider, there are other types:

• Capacitive Voltage Divider: Uses capacitors instead of resistors, useful in AC circuits for phase shift and impedance matching.
• Inductive Voltage Divider: Uses inductors, primarily in AC circuits for applications similar to capacitive dividers but with different frequency characteristics.

See Also

• Ohm's Law
• Series and Parallel Circuits
• Analog-to-Digital Converter (ADC)
• Impedance Matching