Jain College of Engineering, BelgaumAC-Lab Manual EXPERIMENT 1 ACTIVE SECOND ORDER FILTERS: LOW PASS FILTER AND HIGH PASS FILTER Aim: a)Todesign a Second order Butterworth Low pass filter for a given cut off frequency, fH= 1KHz .Draw the frequency response. b) Todesign a Second order Butterworth High pass filter for a given cut off frequency, fL= 1KHz .Draw the frequency response. Components: IC 741 op amp, resistor, multi output, power supply, signal generator, CRO. Design and circuit: Dept. of Electronics and Communication Engineering 1 Jain College of Engineering, Belgaum Low pass filter AC-Lab Manual Let Vcc=12v , fH =1 kHz , gain Af = 2, to simplify the design calculations set Set R1 = Rf = 10kΩ, FH = R= C= 0.01µf C1 = C2 = 0.01µF = C , Let R2 = R3 = R = 15kΩ now Af = 1+ Rf / R [Af = 2] Rf = 10kΩ let Rf = R1 = 10kΩ Waveform: Dept. of Electronics and Communication Engineering 2 Jain College of Engineering, Belgaum High pass filter: Let Vcc = 12v, fL = 1kHz, gain Af = 2 To simplify the design calculation Set R1 = Rf = 10kΩ FL = R= C1 = C2 = 0.01µF = C AC-Lab Manual Let R2 = R3 = R = 15kΩ C= 0.01µf now Af= 1+ Rf / R -- [Af = 2] 2 – 1 = Rf / R 1 hence Rf = R 1 let Rf = 10kΩ = R1 = 10kΩ Dept. of Electronics and Communication Engineering 3 Jain College of Engineering, Belgaum Waveform: AC-Lab Manual Procedure: Connections are made as per the circuit diagram. Set Vin= 2 to 5V P-P in the function generation. By varying the frequency in the function generator, note down the P-P voltage of the output waveform in the oscilloscope. Plot the frequency response in the given semi log sheet. Find the cut off frequency. Dept. of Electronics and Communication Engineering 4 Jain College of Engineering, Belgaum Tabular Column Low pass filter : AC-Lab Manual Vi=2V Frequency (Hz) Vo Gain=Vo/Vi Gain (dB) 20log10(vo/vin) Result: Cut off frequency (theoretical) = 1KHz. Cut off frequency (practical) =----------- Dept. of Electronics and Communication Engineering 5 Cut off frequency (practical) = ---------- Dept. of Electronics and Communication Engineering 6 .Jain College of Engineering. Belgaum AC-Lab Manual High Pass Filter: Tabular column Vi=2V Frequency (Hz) Vo Gain=Vo/Vi Gain (dB) 20log10(Vo/Vin) Result: Cut off frequency (theoretical) = 1KHz. Design and circuit: Given FL = 5kHz FH = 9kHz BW = 9kHz . signal generator.Jain College of Engineering. power supply. resistor.91kHz For second order band pass filter Af = 1 + Dept.5kHz = 4kHz Fc = √ = √ = 5. Components: IC 741 op amp. CRO. Belgaum AC-Lab Manual EXPERIMENT 2-a ACTIVE WIDE BANDPASS FILTER Aim: To design an active wide band pass filter and to plot the frequency response characteristics fro given frequency v/s voltage gain. capacitor. of Electronics and Communication Engineering 7 . Dept. 20 log (Vo/Vin). Given a sinusoidal input of 2Vp-p Vary the frequency of sinusoidal input from 100 Hz to 100 kHz without changing the input voltage level. Find the gain in dB at each frequency using the formula. Frequency response of the filter in obtained by plotting gain in dB v/s frequency. Belgaum AC-Lab Manual Procedure: Rig up the circuit as shown. At each frequency note down the output peak to peak voltage from CRO.Jain College of Engineering. of Electronics and Communication Engineering 8 . Belgaum Waveform: AC-Lab Manual Dept. of Electronics and Communication Engineering 9 .Jain College of Engineering. Belgaum Tabular Column AC-Lab Manual Vi=5V Frequency (Hz) Vo in volt Gain=Vo/Vi Gain (dB) 20log10(vo/vin) Result: Dept. of Electronics and Communication Engineering 10 .Jain College of Engineering. Belgaum AC-Lab Manual EXPERIMENT 2-b ACTIVE BANDSTOP FILTER Aim: To design an active wide band stop filter and to plot the frequency response characteristics fro given frequency v/s voltage gain. CRO.01 X 10-6 = 2. signal generator.01µF FC = √ R= = √ = 6.7kHz X 6.3kΩ Dept.7 X 10 3 X 0. Components: IC 741 op amp.1) RP = RF = ? RF = (1.586 Af = 1 + Let Rf = R1 = 10kΩ (AF .86kΩ For HPF R = fC = C= 0.586 -1) 10 = 5. capacitor. power supply. resistor.Jain College of Engineering. of Electronics and Communication Engineering 11 . Design and circuit: FL = 5kHz fH = 9kHz Pass band gain of second order filter is given by AF = 1.86 RF = 5. Jain College of Engineering. Dept. Find the gain in dB at each frequency using the formula. Given a sinusoidal input of 2Vp-p Vary the frequency of sinusoidal input from 5 kHz to 9 kHz without changing the input voltage level. At each frequency note down the output peak to peak voltage from CRO. 20 log (Vo/Vin). Frequency response of the filter in obtained by plotting gain in dB v/s frequency. of Electronics and Communication Engineering 12 . Belgaum AC-Lab Manual Procedure: Rig up the circuit as shown. of Electronics and Communication Engineering 13 . Belgaum AC-Lab Manual Tabular Column Vi=5V Frequency (Hz) Vo in volt Gain=Vo/Vi Gain (dB) 20log10(vo/vin) Dept.Jain College of Engineering. Belgaum Waveform: AC-Lab Manual Result: Dept.Jain College of Engineering. of Electronics and Communication Engineering 14 . CRO. probes.0 = From equation 2 = 0.6 = UTP – LTP = 2. 0.0 = 2[ ] Vref Vref = 1. of Electronics and Communication Engineering 15 . Resistors. Design and circuit diagram: UTP = 4v and LTP = 2v UTP > LTP Wrt UTP = Vsat = 12v LTP = Vref Vsat Vref ----------------------1 Vsat Vsat ---------------------.2 Vref + (Vsat) UTP + LTP = 2. Belgaum AC-Lab Manual EXPERIMENT 3 SCHMIT TRIGGER CIRCUIT Aim: Design and testing of the Schmitt trigger circuit using op-amp Components: Op-amps (IC-741). connecting wires and Power chords.Jain College of Engineering. Signal generators.87V ==1. Capacitors.9V Chose R2 = 10kΩ and R1 = 90kΩ Dept.0625 R1 + R2 = 16R2 From equation 1 6. Jain College of Engineering. of Electronics and Communication Engineering 16 . Belgaum AC-Lab Manual Dept. Belgaum AC-Lab Manual Transfer characteristics: Dept. of Electronics and Communication Engineering 17 .Jain College of Engineering. Result: output is observed and analyzed. Belgaum AC-Lab Manual Procedure: Make the connections as shown in the circuit.Jain College of Engineering. Compare with expected value. of Electronics and Communication Engineering 18 . Dept. Apply input check square wave output. Use the X-Y mode of CRO to obtain transfer characteristics note UTP and LTP values. multi meters. Components: IC 741 op amp.125 = 3. spring board. CRO.12 .12 when Vr = 5v Vo max = = 3. D1. D2.5 X 24 = +12v VR(1) = 12V and VR(0) = 0V Vo min = 0 Vo max = 0.5 (8 + 4 +2 + 1 ) = 7. D3 are digital input and may be high (1) or low (0) VR(0) = 0 VR(1) = VR = reference voltage can be selected depending on max analog output required R = (Full scale analog output voltage) / (2N + 1) N. signal generator. patch cords.5v AV = = 3. power supply. Design and circuit: D0 . of Electronics and Communication Engineering 19 .12kΩ Dept. Belgaum AC-Lab Manual EXPERIMENT 4 R2R LADDER Aim: design and testing of R-2R ladder using UA-741 OP-amp.No of digital input R = 2N or % R = Let Vr = 500mV For a 4 bit DAC Vo = (23 D3 + 22 D2 + 21 D1 + 20 D0) VR = 0. resistor.1 = 2.12 Let R1 = 1kΩ Rf = 2. capacitor.Jain College of Engineering. 2V which is logic ‘0’ it’s V0 min = 0. Verify it practically using digital voltmeter. D0 = D1 = D2 = D3 = 0 then V0 =0 theoretically and verify it practically suppose if the input from the digital trainer has min of 0. To measure the resolution is defined as the smallest incremental change Let.Jain College of Engineering.e.2083V.12V. To measure Vmin set all digital input to logic ‘0’ i. Dept.2083V [theory]. D3 = D2 = D1 = D0 = 0 & let LSB D0 = 1 Vo = (VR /24) [0 + 0 + 0 + 1] = 0. Belgaum AC-Lab Manual Procedure: Connect the circuit R-2R ladder network as shown in figure. R = 0. of Electronics and Communication Engineering 20 . Belgaum AC-Lab Manual To measure full scale output voltage full scale output voltage obtained by setting all the input to logic high. i. Theoretically calculated value is verified by measuring its practically Tabular Column Decimal Digital Theoretical Experimental Result: Dept.Jain College of Engineering.125V.e. of Electronics and Communication Engineering 21 . D0 = D1 = D2 = D3 = +5v Vo max = (VR /24) [8 + 4 + 2 + 1] = 3. T TL = 0.693 RB C Let c = 0.50 duty cycle. Bread Board / Linear IC kit.75 duty cycle. (Symmetrical) Components: Resistors.75 T= = d= = 0.25ms W. IC 555 (timer). Probes and connecting wires. Connecting wires. f =1 kHz T = 1ms duty cycle 75% or .3kΩ Dept. Capacitors.Jain College of Engineering. CRO.6kΩ choose RB = 3. Design and Circuit diagram: a) Asymmetric Vcc = 12V . Diode.75ms T = 1ms therefore TL = 0.01µF so RB = 3.75 = 1ms = TH + TL TH = 0. Power Supply. K. Belgaum AC-Lab Manual EXPERIMENT 5-a ASTABLE MULTIVIBRATORS ASYMMETRICAL AND SYMMETRICAL Aim: Design an Astable Multivibrator using IC 555 timer to generate a clock signal of i) Frequency 1 KHz with 0. (Asymmetrical) ii) Frequency 1 KHz with 0. of Electronics and Communication Engineering 22 . of Electronics and Communication Engineering 23 .5 T= = = 1ms = TH + TL w.01µF therefore R = 7.82kΩ . RA =7.1µF = 10.693RC .693 X 0. T.693(RA + RB ) C = 0. Belgaum Similarly TH =0.2kΩ Dept.Jain College of Engineering.75ms AC-Lab Manual (RA + RB ) =0. k. RA = RB = R R= Let C = 0.2kΩ Choose RA = 6. TH + TL = 0.75ms/0.8kΩ Check Vcc = 12V Voc = 2/3 Vcc = 8V VLT = 1/3 Vcc 4V b) Symmetrical f = 1kHz T=1ms duty cycle d = 50% or 0. (Multivibrator output) For the capacitor output at pin no 6 . Belgaum Choose RA = RB = R = 6.Jain College of Engineering. Verify that V UT =2/3Vcc and VLT= 1/3 Vcc. Verify the components and patch chords whether they are in good condition. Dept. of Electronics and Communication Engineering 24 .(capacitor output) Also observe the output waveform at pin no 3 on CRO. measure the maximum and minimum voltage levels.8kΩ AC-Lab Manual Procedure: Asymmetrical: Frequency 1 KHz with 0. Connect the Astable multivibrator circuit using IC 555 timer as shown in the ckt as per the design. Switch on the DC power supply unit Vcc=12V.75 duty cycle. Observer the output waveform at pin no 6 on CRO. Jain College of Engineering.(capacitor output) Also observe the output waveform at pin no 3 on CRO. Connect the Astable multivibrator circuit using IC 555 timer as shown in the ckt as per the design. Verify that V UT =2/3Vcc and VLT= 1/3 Vcc. Dept. Compare the capacitor voltage Vc with output waveform Vo and note that capacitor charges and Vc rises exponentially when output is high. The capacitor C discharges through RB and the diode and Vc falls exponentially when output is low. Belgaum AC-Lab Manual Compare the capacitor voltage Vc with output waveform Vo and note that capacitor charges and Vc rises exponentially when output is high.(Multivibrator output) For the capacitor output at pin no 6 . Symmetrical: Frequency 1 KHz with 0. Observer the output waveform at pin no 6 on CRO. The capacitor C discharges through RB and the diode and Vc falls exponentially when output is low. measure the maximum and minimum voltage levels. of Electronics and Communication Engineering 25 . Switch on the DC power supply unit Vcc=12V.50 duty cycle Verify the components and patch chords whether they are in good condition. Verify the designed value of frequency matches with practical value. Verify the designed value of frequency matches with practical value. Belgaum AC-Lab Manual Waveform: Result: The Astable Multivibrators (Asymmetrical and Symmetrical) are constructed for the given design . Dept.Jain College of Engineering. of Electronics and Communication Engineering 26 . the theoretical and practical values are verified for the obtained waveforms. Design and circuit diagram: Time delay T= 1ms T = 1. signal generator and probes. connecting wires. patch chords.1 RC assume C = 0. Capacitors.1µF R= R = 0. of Electronics and Communication Engineering 27 .Jain College of Engineering. CRO. Bread Board. Components: Resistor.1 X R X 0. Belgaum AC-Lab Manual EXPERIMENT 5-b MONOSTABLE MULTIVIBRATOR Aim: To design a Monostable Multivibrator using IC 555 (timer). IC-555.1µF 1ms = 1. Power supply.09kΩ Choose R = 10kΩ Dept. Verify whether the theoretical values are matching with practical values and observe the outputs. Measure the output frequency ‘f’ using CRO and verify that it is equal to the designed frequency.Jain College of Engineering.. of Electronics and Communication Engineering 28 . Adjust the input frequency of signal generator to 80 HZ and adjust the input pulse amplitude to 12V so as to obtain proper waveform across the capacitor ‘C’. Dept. Connect the Monostable Multivibrator circuit using IC 555-timer as like shown in ckt. Observe the timer output waveform at pin no 3 and measure its higher and lower voltage levels and output across ‘C’ on CRO. Belgaum AC-Lab Manual Procedure: Verify all the components and patch chords. Switch on the DC power supply unit Vcc-12V and apply periodic input trigger pulse at pin no 2 using signal generator as the source. Jain College of Engineering. Belgaum AC-Lab Manual Waveform: Dept. of Electronics and Communication Engineering 29 . Jain College of Engineering. EXPERIMENT 6-a Dept. of Electronics and Communication Engineering 30 . Belgaum AC-Lab Manual Result: The Monostable Multivibrator is constructed for the given design and the theoretical and practical values are verified for the obtained waveforms. Resistors. Capacitors. Wires and Power chords. CRO. Probes.01µF choose C1 = C2 = 0. Design and Circuit Diagram: Emitter modulation Let Vcc = 10V . 1:1 Transformer. Signal Generators.01µF and C3 = 47µF Dept. Inductor. Components Required: Transistor (SL100). Ic = 2mA VBE = 0.6µA Choose 22kΩ = RB Fcarrier = 50kHz = √ let L = 1mH then C = 0. Power Supply.7V VCE = 5V RE = 100Ω IC = β IB therefore IB = RB = = 26. β =75 .3kΩ = 26.Jain College of Engineering. of Electronics and Communication Engineering 31 . Belgaum AC-Lab Manual AMPLITUDE MODULATION: EMITTER MODULATION Aim: To construct an Emitter Modulator to generate Amplitude Modulation (AM) waves at a carrier frequency of 50KHZ and to determine the % modulation index at modulating frequency of 1KHZ and plot the variation of modulation index versus peak amplitude of modulating signal. Jain College of Engineering. Belgaum AC-Lab Manual Envelop detector : Dept. of Electronics and Communication Engineering 32 . Belgaum Waveform: AC-Lab Manual Dept.Jain College of Engineering. of Electronics and Communication Engineering 33 . AC-Lab Manual Verify the design by measuring the VCE and IC . of Electronics and Communication Engineering 34 . correspondingly tabulate the Emax and Emin readings to calculate the % modulation index (%m) . without switching on the RF and AF generators. which is the AM waveform. % m = Emax-Emin/Emax+Emin * 100 Vary the amplitude of AF signal that is VAF . Note down Emax and Emin from the output waveform. Observe the output on the CRO. Switch on the RF signal generator and AF signal generator and adjust fm=1 KHz and fc=50 KHz respectively.Jain College of Engineering. Plot the graph of VAF versus % modulation index (%m) for different VAF. Dept. Calculate the % modulation index by using the formula. Belgaum Procedure: Rig up the circuit as shown in the figure. Tabular column: VAF (volts) Emax(volts) Emin(volts) %m Result: An AM waveform is generated and observed for the given frequencies and %m is verified from the tabular column. connecting wires and Power chords.1µF R> R = 666Ω Select R = 680Ω Dept. Capacitors. Belgaum AC-Lab Manual EXPERIMENT 7 PULSE MODULATIONS: PULSE AMPLITUTED MODULATION Aim: To conduct the experiment to generate PAM signal and also design a circuit to demodulate the PAM signal plot the relative waveform Components : Transistor SL100. Signal generators. Diode 0A79. Resistors. Design and circuit diagram: fc>> i.Jain College of Engineering. probes. Rc>> let fc =15kHz C = 0. CRO.e. Linear IC trainer kit. of Electronics and Communication Engineering 35 . DC power supplies. of Electronics and Communication Engineering 36 . Belgaum AC-Lab Manual Modulator : Demodulation: Dept.Jain College of Engineering. Belgaum AC-Lab Manual Waveform: Procedure: Rig up the circuit as shown in figure. Dept.Jain College of Engineering. of Electronics and Communication Engineering 37 . Set up carrier amplitude to around 2Vp-p and frequency in range 5 kHz to 15 kHz. of Electronics and Communication Engineering 38 . Capacitors. connecting wires. Linear IC trainer kit. DC power supplies. Components: Op-amps (IC-741). AC-Lab Manual Connect CRO around emitter of transistor and observe the PAM waveform. EXPERIMENT 8-a PULSE MODULATIONS: PULSE WIDTH MODULATION Aim: Todesign a Pulse Width Modulation circuit and transmit an analog signal and also demodulate the generated PWM wave using a suitable Demodulation circuit. Design and circuit diagram: Modulation: Design Let RC >> T Time period T = 0.1ms R1 C1 = 10T = 1ms Dept. To verify sampling thermo keep the modulation signal frequency to 2 kHz and carrier frequency to twice of modulating wave and check the other end the demodulation waveform it should match with m(t). CRO. Result: PAM waveform is observed and analyzed. patch chords and Power chords.Jain College of Engineering. probes. Resistors. Signal generators. Belgaum Set up amplitude to around 1Vp-p and frequency 2 kHz. Belgaum Let R1 = 10kΩ C1 = 0. of Electronics and Communication Engineering 39 .01µF Choose R1 = R2 =R3 = 10kΩ AC-Lab Manual fc = = fc = 1.59kHz Circuit: Waveform Dept.Jain College of Engineering. The square wave signal frequency is adjusted to obtain proper pulse width. Apply a reference voltage of the range 1-5V. Set up the message (sine wave) signal of frequency 500HZ and amplitude of 5V P-P.Jain College of Engineering. Belgaum AC-Lab Manual Procedure: Rig up the Modulation circuit. A square/ramp/saw tooth waveform is used as a carrier signal with a 5V P-P amplitude. The Vref is kept at zero and the wave form is observed varying the amplitude and the change in width is also observed. and frequency of 2-3 kHz. The Op-amp offset is kept at zero value. The output waveform is observed and plotted. Increase Vref up to 5 V and repeat the same procedure. PWM should vary on variation of message signal. If the output is distorted then frequency is reduced to get proper output. of Electronics and Communication Engineering 40 . The demodulation circuit is rigged Dept. using an IC 555(timer). Design and circuit diagram: Let pulse of the PPM signal = 50MHz T = 1. let CA = 0.Jain College of Engineering. connecting wires and Power chords. of Electronics and Communication Engineering 41 .CRO. Linear IC trainer kit. Components : Op-amps (IC-741). Capacitors. Result: The pulse width modulation is obtained and the signal is analyzed. Resistors.1RC. Diode IN4007.1µF PWM fc(t) = 3kHz CA = 0. EXPERIMENT 8-b PULSE MODULATIONS: PULSE POSITION MODULATION Aim: To generate PPM signal of given pulse width for a given modulating signal from a PWM signal. DC power supplies.Signal generators. The demodulated output that is the sine wave (message signal) is observed and plotted. Belgaum AC-Lab Manual The PWM output from the modulation circuit is fed as the input to the demodulation circuit.1µF Dept. probes. The demodulated output is also obtained and plotted. IC 555. Jain College of Engineering.5Ω AC-Lab Manual Choose RA = 470Ω Waveform Dept. Belgaum RA = = 530. of Electronics and Communication Engineering 42 . Dept. Analyze the PPM waveform and observe that for each trailing edge of the PWM wave there is pulse positioned and all the pulses are of equal widths and durations. Result: PPM waveform is observed and analyzed. Belgaum AC-Lab Manual Procedure: Rig up PWM modulator ckt and observe the PWM output. The PPM output is observed at pin 3. of Electronics and Communication Engineering 43 . Draw the PPM waveform with respect to the PWM waveform.Jain College of Engineering. Connect the output of the PWM modulator as triggering input of PPM modulator at pin 2 through a capacitor. Probes Wires. of Electronics and Communication Engineering 44 .Resistors.Jain College of Engineering. Design and circuit diagram: IC description: Dept. Belgaum AC-Lab Manual EXPERIMENT 9 FREQUENCY MODULATION USING IC 8038 Aim: To design and generate FM signal using IC 8038 and demonstrate the generation of frequency modulated wave. Components : IC 8038. DRB and Power chords.CRO.Capacitors. Power supply.Signal Generators. Jain College of Engineering. Belgaum AC-Lab Manual Test circuit Dept. of Electronics and Communication Engineering 45 . Jain College of Engineering. of Electronics and Communication Engineering 46 .01µF R= = 10kΩ R = Ra = Rb = RL = 10kΩ Cc = C1 = 0. Belgaum AC-Lab Manual FM generation circuit Design Let fc = 3kHz Fc = Choose Cc = 0.01µF Dept. Rig up the FM generation circuit. Set the amplitude of the modulating signal to 1V and its frequency to 1KHZ. Belgaum AC-Lab Manual Procedure: Rig up the Test circuit and observe the waveforms at pin numbers 2. 3 and 9 generating sine. Wave form: Dept.Jain College of Engineering. triangle and square waves respectively. of Electronics and Communication Engineering 47 . Observe the FM output at pin number 2 on the CRO. of Electronics and Communication Engineering 48 . Design and circuit diagram: Half wave : Waveform Dept. Components: Op-amp UA-741.Jain College of Engineering. Belgaum AC-Lab Manual Result: The Frequency modulated waveform is observed. Resistors. EXPERIMENT 10 HALF WAVE AND FULL WAVE PRECISION RECTIFIERS Aim: To realize the half wave precision rectifier. Diode IN4007. of Electronics and Communication Engineering 49 .Jain College of Engineering. Belgaum AC-Lab Manual Full wave: Waveform: Dept. Jain College of Engineering. Dept. of Electronics and Communication Engineering 50 . Belgaum AC-Lab Manual Result: waveform is observed and analyzed.