Resistors in Series/Parallel Calculator
Resistors in Series/Parallel is evaluated from Resistor R1, Resistor R2 and Resistor R3. The calculation reports Total Resistance - Series and Total Resistance - Parallel.
Results
About the Resistors in Series/Parallel Calculator
The calculator uses a multi formula configuration. Each reported value is read as a direct evaluation of the stored rules with the declared field formats and units.
Formula basis:
Series: R_total = R1 + R2 + R3 +...
Parallel: 1/R_total = 1/R1 + 1/R2 + 1/R3 +...
R_total = 1 / (1/R1 + 1/R2 + 1/R3 +...)
Two resistors: R_parallel = (R1 x R2) / (R1 + R2)
Interpret the outputs in the order shown by the result fields. Optional inputs affect only the outputs that depend on those variables.
Formula & How It Works
The calculation applies the following relations exactly as recorded in the metadata: Series: R_total = R1 + R2 + R3 +... Parallel: 1/R_total = 1/R1 + 1/R2 + 1/R3 +... R_total = 1 / (1/R1 + 1/R2 + 1/R3 +...) Two resistors: R_parallel = (R1 x R2) / (R1 + R2) Each output field is produced by substituting the supplied inputs into the relevant relation and then applying the declared rounding or text format.
Worked Examples
Example 1: Series String — Christmas Lights
Inputs
With Resistor R1 = 50, Resistor R2 = 50, Resistor R3 = 50 and Resistor R4 = 50 as the stated inputs, the result is Total Resistance - Series = 250 Ω and Total Resistance - Parallel = 10 Ω. Each value corresponds to the declared output fields.
Example 2: Parallel Power Distribution
Inputs
With Resistor R1 = 1,200, Resistor R2 = 600 and Resistor R3 = 400 as the stated inputs, the result is Total Resistance - Series = 2,200 Ω and Total Resistance - Parallel = 200 Ω. Each value corresponds to the declared output fields.
Example 3: LED Current Balancing
Inputs
With Resistor R1 = 330 and Resistor R2 = 330 as the stated inputs, the result is Total Resistance - Series = 660 Ω and Total Resistance - Parallel = 165 Ω. Each value corresponds to the declared output fields.
Example 4: Automotive Turn Signal Loads
Inputs
With Resistor R1 = 48, Resistor R2 = 48 and Resistor R3 = 48 as the stated inputs, the result is Total Resistance - Series = 144 Ω and Total Resistance - Parallel = 16 Ω. Each value corresponds to the declared output fields.
Common Use Cases
- Find total resistance of a resistor bank
- Calculate equivalent resistance of parallel LEDs
- Design voltage dividers with proper resistor values