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Impedance/Resistance Calculations

 This portion of this site is intended to help you calculate impedance/resistance levels. You can calculate any unknown value if you know the other two in the equation.

Explanation of Terms

E - stands for voltage, the unit is the Volt.
I - stands for current, the unit is the Amp.
P - stands for power, the unit is the Watt.
R - stands for resistance/impedance, the unit is the Ohm.

The Formulas

R = E / I
R = P / I2
R = E2 / P


  Click the unknown measurement type (Voltage/Current/Power), then enter the two values that you do know, and press the "Calculate Power" button to get your answer. If you have more than one value to calculate, just change the value(s) you want to adjust and click the button again (if you change to a new measurement type - be sure to click the reset button or the values shown will be incorrect).

Which number is unknown ?

Voltage  Current  Power 

Enter Voltage Volts
Enter Current Amps
Enter Power Watts

Resistance/Impedance =  Ohms

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