Voltage Dividers and Current Dividers

7-1: Series Voltage Dividers
7-2: Current Dividers with Two Parallel Resistances
7-3: Current Division by Parallel Conductances
7-4: Series Voltage Divider with Parallel Load Current
7-5: Design of a Loaded Voltage Divider

7-1: Series Voltage Dividers

  • VT is divided into IR voltage drops that are proportional to the series resistance values.
  •  Each resistance provides an IR voltage drop equal to its proportional the part of applied voltage:

  •  This formula can be used for any number of the series resistances because of the direct proportion between each voltage drop V and its resistance R.
  •  The largest series R has the largest IR voltage drop.

7-1: Series Voltage Dividers

  • The Largest Series R Has the Most V

7-1: Series Voltage Dividers

  • Voltage Taps in a Series Voltage Divider
  • Different voltages are the available at voltage taps A, B, and C.
  • The voltage at each tap point is the measured with respect to ground.
  • Ground is the reference point.

Fig. 7-2b: Series voltage divider with voltage taps

7-1: Series Voltage Dividers

 

7-2: Current Dividers with Two Parallel Resistances

7-2: Current Dividers with Two Parallel Resistances

7-3: Current Division by Parallel Conductances

  • For any number of parallel branches, IT is divided into
    the currents that are proportional to the conductance of the
    branches.
  • For a branch having conductance G:

7-3: Current Division by Parallel Conductances

7-3: Current Division by Parallel Conductances

7-4: Series Voltage Divider with Parallel Load Current

Voltage dividers are often used to tap off the part of applied voltage for a load that needs less than the total voltage.

7-4: Series Voltage Divider with Parallel Load Current

7-4: Series Voltage Divider with Parallel Load Current

7-5: Design of a Loaded Voltage Divider

7-5: Design of a Loaded Voltage Divider

7-5: Design of a Loaded Voltage Divider