Try it
2 resistors in parallel - shared rails, more paths for current
Total resistance132 Ω
Understand the result
What's going on
Wire resistors side by side instead of end to end and current suddenly has more than one path home. More paths means less overall opposition - the combined resistance always ends up lower than the smallest single resistor in the group.
The formula
1 / R_total = 1/R1 + 1/R2 + 1/R3 + …
Show the derivation, mnemonic, and worked example
Build it up
Each resistor lets through a share of current proportional to how easily it conducts - its conductance, which is just 1 ÷ R. Add more paths and you add more conductance, so the shares add up. To turn that combined conductance back into a resistance, flip it once more at the end.
Worked example
Worked example
R1 = 220 Ω, R2 = 330 Ω
1/R_total = 1/220 + 1/330 = 0.00758
R_total = 1 ÷ 0.00758 ≈ 132 Ω
