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.
Vx = Rx/Rt * Vin
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.