UFMFJT-30-1 Principles of Electrical Engineering Lab Sheet (RLC Parallel Resonant Circuit Response) RLC Parallel Resonant Circuit Response [Maximum Marks 30] The circuit described here form the tuning components for Oscillators in Transmitters and Radio Receiver. Equipment and Components Required: Digital Storage Oscilloscope (DSO), Function Generator, Breadboard, Connection Leads, Resistor 2.7k2, Inductor 10mH and Capacitor 0.1μF. R 2.7K Sig Gen Vin L 10mH (+Rdc) DSO 1 (Y1) DSO 2 (Y2) C 0.1μF Sig Gen & DSO Ground Parallel RLC Tuned Circuit Task 1. Construct the Parallel Tuned Circuit shown above on breadboard, and apply 10Vpp sine waveform to the input point with reference to ground. [5 Marks] Task 2. Monitor this on DSO connected to input DSO 1 (Y1) and with DSO 2 (Y2) across the C and L, Observe and record the amplitude of the sinewave on Y2 by varying the frequency of signal generator across the spectrum from 20Hz to 50 KHz. Record values (at least between 10 and 15 readings) that will enable you to plot the response on log- linear graph paper. Sketch both amplitude and phase plots. [12 Marks] Page 1 of 2 UFMFJT-30-1 Lab Sheet (RLC Parallel Resonant Circuit Response) Principles of Electrical Engineering Task 3. Determine the Resonant Frequency (i.e., the frequency peak) which should coincide with: 1 F 211√ LC Task 4. [1 Mark] From the two points where the voltage falls to 0.707 of the maximum voltage, (the 3dB), determine the bandwidth of the circuit, i.e., the response to frequencies either side of the Resonant point, or the Selectivity. [2 Marks] This range of frequency is mainly due to the circuit resistance and the magnification factor or Q of the Inductance: Q = Fres BW Task 5. Discussion on Results and Observations: Summarise the whole lab session in your own words and conclude what did you gain from this exercise? Think and write down the possible objectives that you may reflect on. Explain your experience of analysing electronic circuits that use passive components such as resistor, capacitors and inductors. What are the main differences between the previous lab circuit and parallel resonant circuit? What are the main applications of these types of circuits are used? What are the drawbacks of these circuits? Comment on the skills you gained in this lab session – how do you feel about the session in terms of understanding the concepts given in the lecture? [10 Marks] Page 2 of 2