Theory - 20 :- Measuring Capacitance and Capacitive Reactance

 

1. Capacitance (C)

Capacitance is the ability of a component (a capacitor) to store an electrical charge. It is defined as the ratio of the charge (Q) stored on a conductor to the potential difference (V) across it.

• Formula: 

  
  
  

• C: Capacitance, measured in Farads (F).

• Q: Charge, measured in Coulombs (C).

• V: Voltage, measured in Volts (V).

• A Farad is a very large unit, so capacitance is often measured in microfarads (uF) or picofarads (pF).

🛠️ Measurement Techniques for Capacitance

Capacitance is primarily measured using specialized instruments:

2. Capacitive Reactance (Xc)

Capacitive Reactance is the opposition offered by a capacitor to the flow of alternating current (AC). It is analogous to resistance in a DC circuit, but unlike resistance, it does not dissipate power. Reactance is dependent on the signal frequency.

Formula:

🛠️ Measurement Techniques for Capacitive Reactance

Capacitive reactance is typically calculated rather than measured directly, as it depends on both capacitance and frequency. However, it can be determined experimentally using Ohm's Law for AC circuits.