Experiment 10 Alternating Current Circuit

Topic: Alternating current circuit
Title: Reactance of a capacitor
Objective: To investigate the variation of reactance of a capacitor with frequency
Theory: The theory is being discussed in STPM PHYSIC

Apparatus:
a) A signal generator

b) Two multimeter with 0 - 10 mA current range and 0 - 10 V voltage range respectively. or we can used two multimeter.

c) Some connecting wires
d) A 1000 pF (102) ceramic capacitor






Procedure:
i) The circuit is set up as shown in Figure 19. A multimeter that is set to 0 - 1 mA is used to measure current and another multimeter is set to 0 - 10 V to measure voltage.

Figure 19.

ii) The experiment is started with the a.c. supply of the signal generator at frequency f = 2.0 kHz and its voltage is adjusted so that the voltage V across the capacitor is around 5.0 V. The value of V and the current I is recorded through the capacitor.
iii) Step (ii) is repeated by increasing f gradually to about 10 kHz and the corresponding V and I is recorded.
iv) The table of f,V,I, X_c ,and 1/f is tabulated.
v) A graph of X_c against f and a graph of X_c againt 1/f  are plotted.
By using a suitable graph in (v), the capacitance of the capacitor is determined.