Practical - 22 :- Measure Capacitive Reactance At Different Frequencies

 Measure Capacitive Reactance and Impedance of RC Circuit

The primary goal of this task is to calculate and record the theoretical and measured values of capacitive reactance ($X_C$) and impedance ($Z$) of an RC series circuit at different frequencies.

Requirements (Setup Components)

• RC Circuit: A resistor (R) and a capacitor (C) connected in series.

• Signal Generator (SIG GEN): Provides an AC voltage (sine wave) at variable frequencies.

• AC Milliammeter (A): To measure the total current (I) in the series circuit.

• Voltmeter/CRO (Cathode Ray Oscilloscope): To measure voltages, specifically the output voltage (VG) of the generator, the voltage across the capacitor (VC), and the voltage across the resistor (VR).

Procedure 

1. Select Components: Connect the given resistor R and capacitor C in series.

2. Set Up: Connect the entire circuit as shown in the provided figure (Fig. 1).

3. Generator Settings: Set the output of the Signal Generator to a sine wave, 12 Vrms, at a frequency of 1 kHz.

4. Use CRO: Use a CRO to set the frequency exactly to 1 kHz (if necessary).

5. Initial Power Up: Put the switch (SW) to the ON position.

6. Measure and Record:

• Record the output voltage (VG) of the signal generator.

• Record the current (I) from the AC Milliammeter.

• Measure and record the voltage drop across the capacitor (VC) and the voltage drop across the resistor (VR) of the circuit.

Note: The lab manual states that I is equal to VG/Z because VC and VR are out-of-phase (they do not simply add up).