Experiment EB1: FET Amplifier Frequency Response Learning Outcome LO2: Analyse low and high frequency response of amplifiers. Apparatus Equipment required Components required Power Supply – 1 N-channel JFET 2N5457 – 1 Oscilloscope – 1 Resistor 10k (1/4W) – 2 Digital Multimeter – 1 Resistor 3.3k (1/4W) – 1 Breadboard – 1 Resistor 3.9k (1/4W) – 1 Function Generator – 1 Resistor 22k (1/4W) – 1 Mylar Capacitor 0.47F – 2 Mylar Capacitor 0.1F – 1 Mylar Capacitor 0.01F – 1 50 k potentiometer -- 1 Objectives: Construct and test a voltage amplifier using N-channel JFET device in a common source configuration Apply the voltage divider biasing method to set the DC operating point (VGSq ,IDSq) . Verify the estimated DC operating point with the measured data. Investigate the effect of frequency changes on the voltage gain of the amplifier, measure its frequency response and obtain its operating bandwidth. Important Notes All related calculation questions that does not require experimental data must be answered before coming to the lab. You are required to show all the calculation steps when requested by the lab instructor. During the evaluation session, your lab instructor may request you to demonstrate how the measurement data is obtained and explain your experimental results. Report Submission You must obtain the signature of the Instructor after completing each section of the experiment. Together with Rubric assessment form, Submit your report to the Lab Supervisor, immediately after the experiment. Background Theory An amplifier is a circuit that increases/decrease the signal value and in this experiment the signal to be amplified is the voltage. In this experiment you are going to investigate frequency response characteristic of a voltage amplifier circuit using the N-channel JFET device
Experiment EB1: FET Amplifier Frequency Response Lab Report (Together with Rubric form, Submit your report on the same day immediately after the experiment) Name: ________________________Student I.D.: _______________Date: __________ Majoring: ____________________ Group: ____________ Table No.: ____________ 1. Table E1: Measured resistance values 3. VDD(meas) = ________ V, VG(cal) = ________ V 4. Table E2: Measured DC voltages 7. Graph E1: vin and vL waveforms at 200 kHz Time base : ______ s/div, CH1 (vin) : ______ V/div, CH2 (vL) : ______ V/div 8. ________ at 200 kHz 9. Table E3: Measure VL(pp) and Vin(pp), and calculated AV f /kHz 1 2 5 10 20 40 60 80 100 200 500 550 VL(pp) /V Vin(pp) /V Av(dB)
STUDENT'S NAME: ID NO: SUBJECT CODE AND TITLE: EEN1026 ELECTRONICS 2 EXPERIMENT EB1 - FET Amplifier Frequency Response EXPERIMENT DATE: TIME: Criteria 1 (Need Improvement) 2 (Satisfactory) 3 (Good) 4 (Excellent) Rating Awarded by Assessor Data Collection and Setting up the Experiment 1 Ability to construct the amplifier circuit on the breadboard Unable to construct the amplifier circuit, and not asking for help. Able to construct the amplifier circuit partially. Able to construct the amplifier circuit. Able to construct the amplifier circuit correctly, with neat and tidy placement of components and jumper wires 2 Ability to set-up the power supply for the circuit, the function generator to the amplifier and to connect the oscilloscope to display the waveform Unable to the DC or AC input to the amplifier, and not asking for help. Able to the DC and AC input to the amplifier partially. DC and AC input to the amplifier is correctly setup. DC and AC input to the amplifier is correctly setup and the waveforms are visible in the oscilloscope. Analysis and Conclusions 3 Ability to extract the midband amplifier's characteristics. No voltage gain is observed, and not asking for help. No voltage gain is observed, but the waveforms are approximately at opposite phase. Voltage gain is more than unity, with the input and output at approximately opposite phase. The voltage gain is fair, with the input and output at opposite phase. 4 Ability to extract the amplifier's complete frequency response. There is no difference between the low-, mid- and high-frequency response of the amplifier. Minor differences between the low-, mid- and high-frequency response of the amplifier. Low-, mid- and response of the amplifier shows some difference. Low-, mid- and high-frequency response of the amplifier is clearly seen on a graph. 5 Ability to answer the questions in by Oral Assessment Not able to answer the question, no attempt was made to answer Able to answer questions with some basics answers and demonstrate some attempts to to the text books, notes, lab sheet Able to answer most part of the questions, with some explanations and elaborations and demonstrate some attempts to to text books, notes or lab sheet Answered all correctly with proper explanations and elaborations, without a need to refer to any references. Note: This form is to be attached together with the Lab results