Voltage Divider Rule

Statement:

The voltage drop across a series resistor is directly proportional to the magnitude of its resistance.

Voltage Divider Circuit and Formula

Consider a series circuit comprising of ‘n’ total resistors.

The voltage divided across resistors Rx can be found from formula:

Let’s understand it in series circuit with two resistors.

VDR in Two Series Resistors

Find voltage divider across R2.

From formula:
Vx = Rx/Rt * Vin

Here

Rx = R2 = 8 kohm

Rt = R1 + R2 = 4 kohm + 8 kohm = 12 kohm

Vin = 12 V

Vx = Rx/Rt * Vin = (8 / 12) * 12 = 8 kohm

VDR for Three Resistors

Let’s solve it for three resistors.

Find voltage across resistor R2.

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