• Astrophysics • Electricity • Electromagnetism • Energy • Fields • Force • Mechanics • Momentum • Nuclear Physics • Quantities & Units  • States of Matter • Waves • Key Experiments ### Voltage divider formula

So, how is the voltage divider rule applied to electric circuits? Look at the diagram above: there is n number of resistors, and we want to take the voltage output from R1, so we want to calculate the voltage value of R1. The formula for finding the voltage value of R1 (VR1) is

Let’s break this down:

In the circuit below, the given values for the resistors are R1 = 3Ω, R2 = 7Ω, and R3 = 5Ω. Find the output voltage (Vo).

SolutionWe take the output voltage (Vo) from the R3 resistor’s poles, which means it will be the same value as R3 resistance’s value voltage. To calculate the voltage value of R3, we can put the given values into the voltage divider equation:

From this calculation, we can find the output voltage:

In some sources, you may see that the voltage divider circuit is a little more simplistic. To help you feel comfortable with both voltage divider diagram types, let’s look at another example below. In the circuit below, the given value for the input voltage (Vin) is 20 volts and the given values for the resistors are R1 = 5Ω  and R2 = 5Ω. Find the value of the output voltage (Vo).

Solution

To solve a question in this diagram style, you must first understand what it represents. This is a complete loop circuit, and it is shown below.

The point shown as Vin in the first diagram shows the positive pole of the voltage source, and the ground resembles that the circuit is a loop connecting to the negative pole of the source Vin. Now let’s apply the voltage divider equation to find the output voltage (Vo), which is equal to the voltage value of R2.Let’s put the values in their correct places in the equation:

## Where are voltage dividers used?

Voltage dividers are used to control the level of a signal and to test voltages. They are also used for the bias of active components in amplifiers. Voltage dividers are found in multimeters as well.

### High voltage measurement

If you need to measure high levels of voltage, a voltmeter alone may not be enough. This is where voltage dividers come in handy. By applying the voltage across the voltage divider, the output voltage can be measured by a voltmeter. The output voltage is lower than the input voltage, but it can be multiplied to determine the original voltage. So, voltage dividers can help measure high levels of voltage.

### Sensor measurement

With the voltage dividers, a microcontroller can read the resistance value of a sensor. To create a voltage divider, the sensor is wired in series with a known resistance. Then, a fixed voltage is applied across the divider. The centre tap of the voltage divider is connected to the analogue-to-digital converter on the microcontroller. This allows the microcontroller to read the tap voltage and calculate the resistance of the sensor using the observed voltage, determined resistance, and voltage. This way, a microcontroller can accurately read the resistance value of a sensor.

### Logic level shifting

In addition to measuring sensor resistance, voltage dividers are also useful as logic level shifters. Logic level shifters are used to connect two logic circuits in series with each other. However, logic circuits operate at 5V, while others operate at 3.3V. If we connect these two circuits directly, the 5V output from the first circuit can damage the second circuit over time, since its input value is only 3.3V.

To solve this problem, a voltage divider circuit can be connected in series between the two circuits. The voltage divider circuit has an output ratio of 3.3/5, which means that it will reduce the voltage from the first circuit to a safe level for the second circuit. By using a voltage divider in this way, logic circuits operating at different voltage levels can be connected safely and effectively.

Voltage Divider - Key takeaways In electronics, a voltage divider is a fundamental and important electric circuit that is used to transform a large voltage into a smaller value. Voltage dividers are used to control the level of a signal and to test voltages. They are also used for the bias of active components in amplifiers.Voltage dividers are used in sensor measurement, high voltage measurement, and logic level shifting. The output voltage of a voltage divider can be found from the resistance value of the output component divided by the total series resistance and multiplied by the voltage value of the source.

## Voltage Divider

What does a voltage divider do?

A voltage divider is used to scale up or scale down the voltage of a source for different purposes.

How do you build a voltage divider?

You can build a voltage divider using two resistors connected in series and an input voltage.

What is a voltage divider circuit?

A voltage divider is a circuit that consists of a series of resistors. The divide-down ratio is set by two resistors, and the output voltage is a fixed proportion of the input voltage.

How do you apply the voltage divider rule?

After you note down the variables, input voltage, the resistance of the resistor (which the output voltage is measured on), and the total series resistance, then the output voltage of a voltage divider can be found from the resistance value of the output component divided by the total series resistance and multiplied by the voltage value of the source.

How do you calculate the voltage divider?

After you note down the variables, input voltage, the resistance of the resistor (which the output voltage is measured on), and the total series resistance, then the output voltage of a voltage divider can be found from the resistance value of the output component divided by the total series resistance and multiplied by the voltage value of the source. 14-day free trial. Cancel anytime.    Join 10,000+ learners worldwide. The first 14 days are on us 96% of learners report x2 faster learning Free hands-on onboarding & support Cancel Anytime