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Determine Voltage Drop Across Resistors

How to calculate voltage drop across series resistors.

  1. AtomSoft
    How to calculate voltage drop across series resistors.

    Step 1

    Determine current of total resistors across the series.

    (I = Current/V=Voltage/R(t)=Resistance Total)

    I = V / R(t)
    I = 9 / (2k + 5k + 10K)
    I = .53 mA​

    Step 2

    Now that we have the Current across the resistors we can calculate the voltage across EACH resistor.

    I = Current
    Vx = Voltage (x = Current Value across X Resistor)
    Rx = Resistor value(x = resistor#)

    V = I x Rx

    V1 = .53 mA x 2k
    V1 = 1.06V

    V2 = .53 mA x 5k
    V2 = 2.65

    V3 = .53 mA x 10k
    V3 = 5.3V

    V1 + V2 + V3 = 9.01 (voltage is 9V only 9.01 because i rounded up from .529 to .53) At .529 you can see barely a difference:

    V Total= 8.993V​

    Also If the resistors are all the same value its easier.

    So just add them up:

    I = V / R(t)
    I = 9 / (5k + 5k + 5K)
    I = .6 mA


    V = I x Rx

    V1 = .6 mA x 5k
    V1 = 3V
    so since all Resistors are same value:
    V2 = 3V
    V3 = 3V

    Also To get different values for like switches just use gnd as a start point and the end of each resistor and a end point. This way you get 3 switches from this each having different voltages

    SW1 = 3V
    SW2 = 6V
    SW3 = 9V

    So I hope someone can learn something from this.

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  1. ElectroMaster
    Great work AtomSoft, this is one of our most popular articles!