Basics calculator
Series & parallel
In series the paths add up; in parallel the openings add up, and the total shrinks.
Free. It runs in your browser: nothing to install.
The example, worked out
Given
- Parts
- Resistors
- Arrangement
- In parallel
- Values
- 1k, 2k2, 4k7
Working
- the inverses add up
Results
The formulas
- R = R1 + R2 + …resistors and inductors add in series
- 1/R = 1/R1 + 1/R2 + …in parallel the inverses add; capacitors do it the other way round
The usual traps
- Capacitors add in parallel, not in series.
- The parallel total is always below the smallest part.
Questions
How do resistors and capacitors add in series and in parallel?
R = R1 + R2 + …: resistors and inductors add in series. 1/R = 1/R1 + 1/R2 + …: in parallel the inverses add; capacitors do it the other way round.
What does it give for typical values?
1 kΩ, 2.2 kΩ, 4.7 kΩ in parallel: 600 Ω. Total, parallel: 600 Ω.
What are the usual mistakes?
Capacitors add in parallel, not in series. The parallel total is always below the smallest part.
In the app
Your circuit, drawn live
Change a value: the schematic redraws with your numbers on the parts.
The part you can buy
Results rounded to standard values (E12, E24, E96) and power ratings.
The working, shown
Every step written out. Try it first by hand, then check.
Into your notebook
One click puts the circuit on a sheet of your project.
Open the calculatorOpens in the app on 1 December, with Circuit Notebook 1.0
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