How Capacitive Reactance Works?
Capacitive reactance (symbol XC) is the resistance offered by a capacitor to an AC (alternating current) signal. It works like resistance but it changes which depends on the frequency of the signal and the value of the capacitor.
The formula to calculate capacitive reactance is:
XC = 1 / (2 × π × f × C)
Where:
- XC is the reactance in ohms (Ω)
- f is the frequency in hertz (Hz)
- C is the capacitance in farads (F)
Key Points:
- Reactance is high at low frequencies and low at high frequencies.
- For DC (0 Hz) reactance is infinite—capacitor blocks it.
- For high-frequency AC, the capacitor easily allows current to pass.
Example:
- A 1 µF capacitor at 50 Hz has a reactance of about 3.2 kΩ.
- The same capacitor at 10 kHz will have a reactance of just 16 Ω.
This is why, capacitors are commonly used to filter out DC and pass AC especially in power supplies and signal processing.
Capacitive Reactance Calculator
Calculating Capacitance Output Current Capacity
Now since we know how to calculate the reactance of the capacitor, we can now easily calculate the output current capacity of that capacitor using the following Ohm's law calculator tool.
Enter the reactance value inside the "Resistance" field.
Add the RMS voltage of the AC voltage or the DC voltage, in the "Voltage" field.
Press "Calculate" to get the final result, that is the maximum current delivering capacity of the capacitor.
Questions & Answers
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Thank you! Appreciate your response very much!!
What is the meaning of c2 in your FM circuit? Please show me a photo of it.you said you can tune it with screw driver
simply calculate-1 mikrofarad on 230VAC,50 Hz is about 70mA
i want to connect capacitor to the Mains in Series with the another circuitry ( series Impedance application )
Now which type ( polypropelene ,Metalised Polypropelen ,Film Foil type AC) & make like vishay ,deki ,ctr?
i will calculate reactance value as per my need.
It can be of this type:
Thanks for prompt reply.
sir may i choose interference suppression x2 type of vishay make ?
Yes definitely you can use them!
How to calculate the voltage drop across a capacitor. For example if I am connecting 135J in series to the phase what would be the voltage available on the other side
There will no voltage drop when AC is passed through a capacitor, there will be drop in current.
If you connect 220V to a capacitor, the other side will also be 220V.