Capacitive reactance-When AC current passes through a circuit with capacitance, the capacitor has the function of hindering AC current from passing through, which is called capacitive reactance.
Capacitance reactance is calculated as follows
Xc=1/ω×C=1/2π×fc
Xc- capacitive reactance value of capacitor; ohm
ω-angular frequency
π-3.14
F- frequency, which is 50HZ for power frequency
C- capacitance value farad
The capacitor in AC circuit is Xc=1/2πfc of capacitor.
For example, f=50Hz in ordinary lighting circuit.
Then 104 capacitive reactance xc = 10 6/2 * 3.14 * 50 * 0.1 = 16 kω.
101104 one thousandth of capacity Xc=16MΩ.
1% of the capacity of 102104, then Xc=1600KΩ
Different sizes of capacitive reactance are also different, similar to resistor sizes. In the rectifier circuit, the larger the parallel capacitance, the slower the charging and discharging speed, and the better the voltage stabilizing effect. The circuit is equivalent to a river, and the capacitor is equivalent to a reservoir beside the river. The larger the reservoir area, the stronger the ability to maintain the water level. Because the capacitance is related to frequency, different places need different capacitance values. For example, a capacitor is connected in series with the AC gear of the pointer multimeter to block the local DC. When selecting the capacitor, the capacity needs to be calculated as appropriate. When the capacity is too small, the AC voltage value measured by its capacity resistance becomes smaller, and when the capacity is too high, it is easy to burn out. Internal resistance of AC voltage file is greater than 10 mω.
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