Voltage divider method

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  1. Introduction to the Voltage Divider Method and the Voltage Divider general formula:
  2. A review on Ohm's Law.
  3. What is the Voltage Divider Method?
  4. How is the voltage divider a shortcut for Ohm's Law?
  1. Voltage Divider Method for a Simple Circuit with Resistors in Series
    Find the voltages used up by each resistor using the Voltage Divider Method.

    Voltage Divider
    1. Voltage Divider Method for Circuits with Both Series and Parallel Configurations

      Voltage Divider
      1. Find the total resistance of the entire circuit.
      2. Find the voltage used by each resistor.
      3. Find the current flowing through each resistor.
        1. Find the current using Ohm's Law
        2. Find the currents using Kirchhoff's 2nd Rule
    2. Voltage Divider Method for the Ultimate Circuit Question

      Voltage Divider
      1. Find the total resistance of the entire circuit.
    Topic Notes

    In this lesson, we will learn:

    • A review on Ohm’s Law and how to manipulate the equation (V=IR) to solve for voltage, current, and resistance.
    • How to solve problems for voltage and resistance with a shortcut equivalent of Ohm’s Law; the Voltage Divider Method general formula we will be using is:
    • What is the relationship between voltage, current, and resistance?
      • Vx=Vtotal ⋅ RxRtotal V_{x} = V_{total} \, \cdot \, \frac{R_{x}} {R_{total}}
    • When and how to use the Voltage Divider Method to skip to solving questions for voltage and/or resistance without having to first solve for current.
    • How we can use the Voltage Divider Method to supplement Ohm’s Law to help us in this chapter


    • The Voltage Divider Method is a formula we can utilize as a shortcut to Ohm’s Law (V=IR)(V=IR) in certain casesβ€”when the electric circuit question is asking for voltage and/or resistance, it is no longer necessary to solve for the electric current before calculating the voltage across center resistors.

    • The general formula for the Voltage Divider Method is as follows:
      • Vx=Vtotal ⋅ RxRtotal V_{x} = V_{total} \, \cdot \, \frac{R_{x}} {R_{total}}

    • Where:
      • VxV_{x} is the voltage drop across a particular resistor xx
      • VtotalV_{total} is the total voltage of the circuit supplied by the battery/source
      • RxR_{x} is the resistance of a particular resistor xx
      • RtotalR_{total} is the total, combined sum of resistances of the circuit

    • In some cases, we will want to apply the voltage divider to only a section of the circuit (i.e. the parallel component only)β€”not to the entire circuit
      • In those cases, the total voltage will reflect the voltage amount of that portion only (i.e. the equivalent parallel resistance; VparallelV_{parallel})
      • And, the total resistance will reflect the sum of resistances of that portion only (i.e. RparallelR_{parallel})
      • In other words, you would replace the variables with β€œtotal” subscripts with the portion amount only (i.e. VtotalV_{total} = VparallelV_{parallel} and RtotalR_{total} = RparallelR_{parallel})

    • If the question provides the current II as a given, it usually hints that one or more parts of the question will not require the voltage divider (since the voltage divider formula does not include current)
      • If the question asks to solve for the current, it will require Ohm’s Law (V=IRV=IR) and can be supplemented by the voltage divider method depending on the question