Begin by entering the resistance values into the resistance input box. Please
be sure to separate each resistance by a comma. There is no limitation as to the
number of entries. Click on the "Calculate Resistance" button for the returned
parallel resistance value and the number of resistor values entered. Note: Parallel
resistance is NOT the same as averaging. Parallel resistance formula: RT = 1 /
((1 / R1) + (1 / R2) + (1 / R3) + ...). In this formula, RT is the total (paralleled)
resistance of the circuit, R1 is the resistance of the first resistor, R2 is the
resistance of the second resistor, R3 is the resistance of the third resistor,
and so on. Please remember that RT is, with no exception, always smaller than
the lowest value resistor in parallel. Input value is assumed to be ohms and returns
as ohms.
An example (and test) of the formula is to use three resistors, 100 ohms, 200
ohms and 300 ohms, all in a circuit in parallel. The total (parallel) resistance
would be 1 / (1/100 (.01) + 1/200 (.005) + 1/300 (.00333)) or about 54.555 ohms.
Accuracy is good to the capability of your browser, generally 18 characters in
the display window. NaN is an indication of an error in data entry or calculation;
do the process again paying close attention to your data entry.