Resistors in Series
When resistors are connected one after each other this is called connecting in series. This is shown below.
To calculate the total overall resistance of a number of resistors connected in this way you add up the individual resistances. This is done using the following formula:
Rtotal = R1 + R2 +R3 and so on.
Example: To calculate the total resistance for these three resistors in series.
| Rtotal = R1 + R2 + R3 = 100 + 82 + 1 Ohms = 183 Ohms |
Task 1:
Calculate the total resistance of the following resistor in series.
 | Rtotal | = _______________ |
| = _______________ |
 | Rtotal | = _______________ |
| = _______________ |
 | Rtotal | = _______________ |
| = _______________ |
Resistors in Parallel
When resistors are connected across each other (side by side) this is called connecting in parallel. This is shown below.
Two Resistors in Parallel
| To calculate the total overall resistance of a of two resistors connected in this way you can use the following formula: |  |
Example: To calculate the total resistance for these two resistors in parallel.
Task 2:
Calculate the total resistance of the following resistor in parallel.
Three or more resistors in parallel
To calculate the total overall resistance of a number of three or more resistors connected in this way you can use the following formula:
Example: To calculate the total resistance for these three resistors in parallel
Task 3:
Calculate the total resistance of the following resistor in parallel.
Answers
Task 1
1 = 1492 Ohms
2 = 2242 Ohms
3 = 4847 Ohms
Task 2
1 = 5 Ohms
2 = 9.57 Ohms
3 = 248.12 Ohms
Task 3
1 = 5.95 Ohms
2 = 23.76 Ohms