Applied Electricity 1 , May/June 2012
 Questions: 1 2 Main
Weakness/Remedies
Strength

Question 1

AIM: Investigation of the relationship between frequency and current in series LC  circuit.

1. Connect the circuit as shown in Figure 1.
2. Set the frequency of the generator to zero (0.0Hz).
3. Ask the Supervisor to check the circuit connection.

Table 1

 Frequency, f (Hz) 300 600 900 1200 1500 1800 2100 2400 2700 3000 Current, I (mA)
1. Adjust the frequency of the generator to 300 Hz as shown in Table 1.
3. Increase the frequency of the generator by 300 Hz.
4. Repeat steps (f) and (g) until the frequency is up to 3000 Hz.
5. Plot a graph of current I (mA) on the vertical axis against frequency f (Hz)

on the  horizontal axis.

1.  Determine from the graph the resonant frequency.
2. Comment on the current at resonance.

Observation

The candidates were expected to connect the circuit as shown in Fig.1, measure and record in Table 1 current readings, plot the graph f(Hz) versus I(mA), determine the resonant frequency and the associated current from the graph.