Calculation formula of resistance of parallel resistor

by：1/R_and=1/R₁+1/R₂+1/R₃+...1/R_n

For example: 10Ω, 10Ω, 100Ω, 100Ω, the resistance of four resistors in parallel is R _and is:
1/R_and=1/10+1/10+1/100+1/100
1/R_and=22/100
R_and≈4.5Ω

Another example: the resistance of 820Ω, 1.5kΩ two resistors in parallelR_andis：
1/R_and＝1/820+1/1500
1/R_and＝116/61500
R_and≈530.2Ω

Two typical applications for shunt resistors:

1. There is no suitable resistor: when a resistor with a suitable resistance is not found, it can be obtained by connecting multiple resistors in parallel.
2, the resistance power does not meet the requirements: For example, if a 1W 25Ω resistor is needed in the circuit and there is no hand, then four 1/2W resistors with 100Ω resistance can be used in parallel to replace the power distribution evenly, four The resistance of the resistor should be as uniform as possible.