1. Capacitive Reactance

2. Capacitors in AC Circuits

3. Capacitance Capacitance also causes opposition to current flow.
Blocks DC.

4. Capacitance The farad (symbol: F) is the SI unit of capacitance.
It is named after the British physicist Michael Faraday.

5. Voltage
Current
Capacitor in DC

6. ICE

7. I C E Current Capacitance Voltage Current leads Voltage in a
Capacitive Circuit

8. Voltage
Current
Capacitor in AC

9. Voltage Current V = Vpsin(2πft) I = C dv/dt I = C Vp(2πf)cos(2πft)
Vp-Peak Voltage
I = C Vp(2πf)cos(2πft)
2π-Cycle
f-frequency(Hz)
t-time(seconds)
Ip = Vp(2πf)C

10. Ip = Vp(2πf)C
Ip = Vp/R
1/R = 2πfC
R = 1/(2πfC)
Capacitive Reactance
Xc = 1/(2πfC)
C is an Active Component

11. Capacitance in AC Circuits

12. Capacitive Reactance
The opposition to current flow caused by a capacitor is known as capacitive reactance.
Capacitive reactance, as it is opposition to current flow, is measured in Ohms Ω.
The symbol for capacitive reactance is XC.
The formula is:

13. Capacitor Values 1mF = 1 X 10-3F 1μF = 1 X 10-6F 1nF = 1 X 10-9F
1pF = 1 X 10-12F

14. Find the current flowing in a circuit when a 4μF capacitor is connected across a 880v, 2000Hz power supply.
C = 4μF = 4 X 10-6F
Vp = 880V
f = 2000Hz
Find: Ip

15. Xc = 1/(2πfC)
Xc = 1/(2π(2000Hz)(4x10-6F)
Xc = 19.9Ω
Ip = Vp/Xc
Ip = 880v/19.9Ω
Ip = 44.2A