Total Resistance in Series Circuit {*Whether
they are Equal or Unequal*}

Total
Resistance of all Resistors on a Series Circuit =

R1 + R1 + R1 + R1 = Total resistance of that Series Circuit.

**Special Notes:**The
total resistance will increase as you add more resistors to the series
circuit.

**Special Notes:** The
total resistance of all resistors on a series circuit will always be
more than the amount of any one resistor in the circuit, actually the
total resistance will be the sum of all resistors on that series circuit.

Total Resistance in Series Circuit

To find the total resistance of the above drawing with all resistors in a series =

3 ohms + 3 ohms + 3 ohms + 3 ohms = 12 ohms total resistance

**Parallel
Circuits**

Total
Resistance in Parallel [*Equal Resisters*]

Number of resistors in parallel = Total Resistance

**Special Notes:** The
total resistance will decrease as you add more resistors to the parallel
circuit.

To find the total resistance of the above drawing with all equal resistors

resistance = __10
ohm__ =2
ohm total

5 resistors

Total
Resistance in parallel [*Maximum of
two Unequal Resisters*]

__Resistance
of one resistor__ __R1
x R2__ =
Total Resistance

Number of resistors in parallel R1
+ R2

To find the total resistance of the above drawing for two unequal resistors

= __3
x 12__ = __36__ =
2.4 Total ohms resistance

3 + 12 15

Total
Resistance parallel circuit above [*Minimum
of Three or More Unequal Resisters*]

__R1
x R2__ = Y __Y
x R3__ =Resistance Total phase one
of format

R1 + R2 Y + R3

__3ohms
x 12ohms__ = __36__ = 2.4 Resistance

3ohms + 12ohms 15

Total phase 1 of format to find Y. You must carry “ Y ” on to phase 2 of the format to calculate the third resister into the total Resistance Calculation.

Phase 2 = “Y” = 2.4

__2.4 x 4ohm__ {the
third resistor} = __9.6__ = 1.5
ohms Total resistance of circuit

2.4 + 4ohm {the third resistor} 6.4

**Special Notes:** The total resistance
of two or more resistors on a parallel circuit will always be less than
the amount of any one resistor in the circuit.

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