Laboratory Manual - King Fahd University of Petroleum and Minerals

More documents

Recommendations

Info

KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS DEPARTMENT OF ELECTRICAL ENGINEERING Electronic Circuits II – EE303 Experiment # 2 Frequency response of multistage transistor amplifiers OBJECTIVE 1. To measure the frequency response of common emitter (CE) amplifier. 2. To study the effect of the load resistance R L on the frequency response of the CE amplifier. 3. To explore some advantages of using multistage amplifier Common Emitter- Common-Collector amplifier. BACKGROUND A typical common emitter (CE) amplifier is shown in Figure 1. 5V + - Vcc R B1 30k R C1 4.3k C 2 C 1 Q1 1 V out R Sig 1k 1 R L 100k Vsig R B2 10k R E1 1.3k C E 47 Figure 1: Common Emitter amplifier As you have studied in your lectures, it can be shown using small signal ac analysis that: 1. The midband frequency A M gain is given by: vo vbe vo Rin ' A M g mRL (1) v v v R R sig sig be sig in 22
where R R 1 // R 2 // r and ' in B B 1 RL RL // RC1 2. The low frequency pole can be approximated by the pole due to the capacitor assoiciated with the lowest resistance namely C E : 1 wL (2) r RS // RB 1 // RB2 CE ( RE1 // ) 1 3. The high frequency pole can be approximated by the pole due to input capacitance which becomes significantly large because of miller’s capacitance C eq = C ' (1 g R m ) 1 eq in s 1 m L in s 1 L : 1 1 wH (3) ' [ C C ] R // R C g R ( R // R ) ' Where g m RL represents the voltage gain between the two terminals of C μ1 (i.e. the gain between the collector and base of Q1). Since R L is connected at the collector of Q1, changing its value will directly alter both A M and ω H . In order to maintain almost constant gain and hence constant bandwidth a buffer stage or common-collector (CC) amplifier can be used to isolate the load from the basic CE amplifier or C μ1 as shown in Figure 2. Now the input resistance of the CC amplifier (R in2 ) will act as the new load derived by the collector of Q1. The input resistance of Q2 is slightly dependent on R L and hence changing R L will lead to small variation in the gain and ω H . In other words, since the CC amplifier has a relatively small output resistance which can derive various loads while maintaining almost constant gain. Keeping the gain almost constant will also results in constant bandwidth. Also, note that since CC amplifier has usually much larger bandwidth than that of the CE amplifier, the overall bandwidth of the multistage amplifier will mainly be decided by the poles of CE amplifier. + 5V - R Sig Vsig Vcc 1k C 1 1 R B1 R C1 4.3k 30k C 2 Q1 1 2N3904 R B2 10k R E1 1.3k C E R B3 R B4 47 30k 10k 4.3k R E2 2N3904 1 C 3 1.3k 100k R L V out Figure 2: Common Emitter amplifier with Buffer With the buffer connected the midband the various parameters become: v o Rin '' 1. A M g mRL ABuffer (4) v R R sig sig in 23
Page 1 and 2: King Fahd University of Petroleum a
Page 3 and 4: 4. You can use upper or lower case
Page 5 and 6: Detailed model parameters are provi
Page 7 and 8: ‣ Run the program Once you are in
Page 9 and 10: |Av(jω)| [dB] A m F L (jω) F H (j
Page 11 and 12: Spice Transistor Model .model Q2N39
Page 13 and 14: TABLE 2: DETAILED BJT MODEL PARAMET
Page 15 and 16: KING FAHD UNIVERSITY OF PETROLEUM A
Page 17 and 18: SPICE Simulation: SPICE simulations
Page 19 and 20: Table I: Measurement results With C
Page 21: This page to be submitted with the
Page 25 and 26: 4. Use three parastic capacitances
Page 27 and 28: This page to be submitted with the
Page 29 and 30: 1 The output voltage in time domain
Page 31 and 32: 10k Differentiator 1500pF 2 3 7 - 7
Page 33 and 34: A SUBCIRCUIT may be called as follo
Page 35 and 36: 35 6. Construct the differentiator
Page 37 and 38: MINI-SYSTEM Now, you should be appl
Page 39 and 40: vo ( s) R2 / R1 v ( ) s i s 1 R w
Page 41 and 42: DL1 4 5 DIODE DL2 6 4 DIODE VL1 5 0
Page 43 and 44: DEMONSTRATION: NETWORK ANALYZER The
Page 45 and 46: R 1 2 3 7 - 741 + +15V 4 -15V 6 V o
Page 47 and 48: considering the op amp connected as
Page 49 and 50: frequency at, say 1kHz, then the ou
Page 53 and 54: General (bilinear) filter a s a Ts
Page 59 and 60: The filter parameters are as follow
Page 61 and 62: SPICE simulation: 3. Use SPICE simu
Page 65 and 66: +V DD =5V 100k R 2 R D 4.3k C 2 R s
Page 67 and 68: You must have your SPICE output fil
Page 71 and 72: Amplitude Controll Althogh the freq
Page 73 and 74:
73 COMPONENTS 1. Digital Oscillosco
Page 75 and 76:
This page to be submitted with the
Page 77 and 78:
V i 2 3 +15V 7 - 741 + 6 4 -15V R 1
Page 79 and 80:
4. Capacitors: C=0.1μF (2 NOs), 15
Page 81 and 82:
APPENDIX 1. Capacitors and Resistor
Page 83:
83 2. Data sheet for MOSFET # 2N435
Page 87:
87 4. Data sheet for op amp 741.
show all

Laboratory Manual - King Fahd University of Petroleum and Minerals

Create successful ePaper yourself

Delete template?

Save as template?