Voltage Divider Formula: Resistive Voltage Divider, Applications, Questions

Voltage Divider Formula is \(V_{out} = V_{in} \times \frac{R_2}{R_1 + R_2}\). Here, R₁ = Resistor closest to the input voltage (V_in); R₂ = Resistor closest to ground; V_in= Input Voltage; V_out = Output voltage across R₂  which is then divided voltage (1/4 of input voltage). Voltage Divider Circuits can be used to generate many voltage levels from a single supply voltage. The common supply can be a single positive or negative supply, such as +5V, +12V, -5V, or -12V, etc. It can also be a dual supply, such as ±5V, ±12V, etc. Since "Volt," the unit of voltage, reflects the amount of potential difference between two places, voltage dividers are also known as potential dividers. 

Key Terms: Volt, Resistor, Potentiometer, Capacitor, Inductors, Voltage Divider, Voltage, Electric current, Ohm’s law, Kirchhoff’s voltage law

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Resistive Voltage Divider Circuit

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R₁ and R₂ are two resistors that are connected in series in this circuit. Because the two resistors are connected in series, an identical amount of electric current must pass through each resistor element of the circuit because there is nowhere else for it to go. As a result, each resistive element has an I*R voltage drop.

We can use Kirchhoff's Voltage Law (KVL) and Ohm's Law to discover the voltage dropped across each resistor calculated in terms of the common current, I, flowing through them with a supply or source voltage, V_S, applied across this series combination. 

Voltage Divider Main Circuit

Following Ohm's Law, the current flowing across the series network is simply I = V/R. Because the current is shared by both resistors (I_R1 = I_R2), the voltage dropped across resistor R2 in the aforementioned series circuit can be calculated as follows:

I_R2 = V_R2/R₂ = V/(R₁ + R₂)

∴ V_R2 = V_S (R₂ / R₁ + R₂)

Likewise for resistor R₁ as being:

I_R1 = V_R1/R₁ = V_S/(R₁ + R₂)

∴ V_R1 = V_S (R₁ / R₁ + R₂)

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Voltage Divider Formula

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The voltage divider is a series of resistors or capacitors that may be tapped at any point along their length to yield a portion of the voltage applied between their ends.

It comprises a two-resistor electric circuit and a single input voltage supply. A basic voltage divider is depicted in the diagram below. Two resistors are linked in series in this circuit. The voltage divider's output voltage is a function of the input voltage. This circuit aids in determining how the input voltage is distributed among the circuit's components.

A voltage divider divides a voltage between two resistors in a series. We can draw the circuit in a variety of ways, but it should always be the same circuit.

Thus the Voltage Divider Formula is as follows:

\(V_{out} = V_{in} \times \frac{R_2}{R_1 + R_2}\)

• R₁ = Resistor closest to the input voltage (V_in)
• R₂ = Resistor closest to ground
• V_in= Input Voltage
• V_out = Output voltage across R₂  which is then divided voltage (1/4 of input voltage)

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Applications of Voltage Divider

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Voltage Dividers are widely utilized in both analog and digital circuits. The following are some of the most prevalent uses for voltage divider circuits.

Potentiometers

A potentiometer, or simply a POT, is a three-terminal variable resistor. A Voltage Divider circuit with changeable output voltage can be implemented using a potentiometer.  This can be accomplished by connecting the input voltage to the potentiometer's extreme pins and the output to the wiper terminal.

Resistive Sensors (LDR and Thermistor)

LDR (Light Dependent Resistor) and Thermistor are two often used sensors in DIY projects. These two sensors are resistive. The issue is that a Microcontroller, such as Arduino, can only read voltages at the input. You may retrieve the voltage across the resistive sensors (LDR or Thermistor) by putting them in a voltage divider circuit and programming the microcontroller to scale the value accordingly.

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Things to Remember

• Voltage dividers are employed in the measurement of sensors, voltage, logic level shifting, and signal level control.
• Voltage dividers are used in amplifiers to alter the signal level, measure voltage, and bias active components. Voltage dividers can be found in a multimeter and a Wheatstone bridge.
• In power transmission, a capacitive voltage divider is used to compensate for load capacitance and to assess high voltage.
• The voltage divider is only used in circuits when the voltage is regulated by dropping a specific value. It is primarily employed in systems where energy efficiency is not a priority.

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