AC1 Fundamentals Unit 7 – Capacitive Reactance
Exercise 1 – Capacitive Reactance
EXERCISE OBJECTIVE
When you have completed this exercise, you will be able to determine capacitive reactance (XC)
by using calculated and measured values. You will verify your results with an oscilloscope.
EXERCISE DISCUSSION
- Capacitors pass ac current but present an opposition to current flow in the form of an
impedance. - The impedance produced by a capacitor is referred to as capacitive reactance (XC) and is
calculated using this equation. XC = 1/(2πfC)
where XC is the reactance measured in ohms
f is frequency in hertz
C is capacitance in farads
2 π is a constant that indicates that the equation is valid for sine waves only. - Capacitive reactance depends on the frequency of the signal and the capacitance.
- Capacitive reactance and circuit capacitance are inversely proportional.
- Capacitive reactance is independent of the amplitude of the applied signal.