Calculate capacitor current in amps from farads, voltage change and time, or solve for capacitance, voltage change or time, with the charge in C and mAh.

How much the capacitor voltage rises or falls during the time interval, e.g. 12 V to 5 V is 7 V.

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Farads To Amps Formula

The following formula gives average capacitor current for a voltage change over a time interval. It is not a direct conversion from capacitance alone.

Iavg = C ร— ฮ”V / ฮ”t

Variables:

  • Iavg is the average current magnitude in amperes (A).
  • C is the capacitance in farads (F)
  • ฮ”V is the magnitude of the voltage change across the capacitor, in volts (V).
  • t is the time in seconds (s) during which the charge or discharge process occurs

Multiply constant capacitance in farads by the voltage-change magnitude, then divide by the time interval in seconds. This gives average current; instantaneous current can vary. Solving for time assumes constant current, rather than exponential RC charging.

Farads to Amps Conversion Table (I = C ร— V / t; assumes V = 1 V, t = 1 s)
Capacitance (F) Current (A)
0.0000000010.000000001
0.000000010.00000001
0.0000000470.000000047
0.00000010.0000001
0.000000220.00000022
0.000000470.00000047
0.0000010.000001
0.00000220.0000022
0.00000470.0000047
0.000010.00001
0.0000220.000022
0.0000470.000047
0.00010.0001
0.000220.00022
0.000470.00047
0.0010.001
0.00220.0022
0.00470.0047
0.10.1
11
Assumes a 1 V change over 1 s. Using I = C ร— V / t. Values shown in base SI units (F, A).

What is Farads To Amps?

A farad measures capacitance; an ampere measures current. For an ideal capacitor with constant capacitance, a voltage change transfers charge ฮ”Q = C ร— ฮ”V. The average current over that interval is ฮ”Q / ฮ”t. Capacitance alone does not determine current, and the current at each instant need not equal the average.

How to Calculate Farads To Amps?

Use Iavg = C ร— ฮ”V / ฮ”t to calculate average capacitor current.

  1. First, determine the capacitance (C) in farads (F).
  2. Next, determine the voltage-change magnitude ฮ”V in volts (V).
  3. Next, determine the time (t) in seconds (s) during which the charge or discharge process occurs.
  4. Next, use Iavg = C ร— ฮ”V / ฮ”t to calculate average current in amperes.
  5. Finally, calculate the Farads To Amps.
  6. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

capacitance (C) = 10 farads (F)

voltage change ฮ”V = 5 V

time interval ฮ”t = 2 s. The average current is 10 ร— 5 / 2 = 25 A.