Multisim peak to peak voltage

Using Multisim (National Instrument)

Department of Electrical and Computer Engineering, University of Dayton, Spring 2017

PRELAB 3 Instructions:

 Simulate the circuits below in Multisim, obtain oscilloscope screen captures and multimeter

measurements of all simulation results before the laboratory session. Whenever you are

displaying two related signals on the oscilloscope, you should align the ground markers of

both signals as well as choose a proper Volts/Div setting so as to be able to make a meaningful

comparison of the two oscilloscope signals. Measure peak-to-peak voltages of both the input

and the output and the frequency of the output. Make sure you do everything you are asked

to do in order to get maximum points. Show all the obtained screen captures in your prelab

report.

 Prepare a typed up report. Submit a pdf of your report electronically on Isidore. A formal write up is not required. However keep your report annotated, clear and succinct. That means you still need to label figures and tables if included and clearly state questions you are answering

NOTE ABOUT THE VIRTUAL AGILENT OSCILLOSCOPE PROBES IN SIMULATION IN THE FIGURES BELOW.

PLEASE TAKE NOTE OF THE FACT THAT IN FIGURE 1 BELOW, FOR INSTANCE, THE TWO PROBES OF THE

VIRTUAL AGILENT OSCILLOSCOPE IN SIMULATION ARE THE “X” AND “Y” PROBES. THE GROUND

PROBE FOR EACH “X” AND “Y” PROBE LIKE YOU HAVE ON THE REAL AGILENT OSCILLOSCOPE IS NOT

SHOWN IN THE FIGURE (AND IS NOT VISIBLE IN SIMULATION) HOWEVER ALL VOLTAGE WAVEFORM

MEASUREMENTS ON THE VIRTUAL OSCILLOSCOPE ARE WITH RESPECT TO THE INVISIBLE GROUND OF

THE CIRCUIT IN SIMULATION. WITH THIS IN MIND, IT SHOULD BE OBVIOUS THAT FIGURE 1 BELOW

SHOWS “X” PROBE IS MEASURING THE VOLTAGE ON THE OUTPUT OF THE FUNCTION GENERATOR

WITH RESPECT TO GROUND AND “Y” PROBE IS MEASURING THE OUTPUT VOLTAGE AFTER THE DIODE

WITH RESPECT TO GROUND.

You are required to simulate the circuits on Figure 1, Figure 2 and Figure 3 for values of load

resistance R1 = 330Ω, 7.5kΩ, and 120kΩ. Include oscilloscope captures, voltage and current measurements. Below, I show you what you should get for R1 equal to 100Ω and 270Ω, but, again, you are expected to do it for R1 = 330Ω, 7.5kΩ, and 120kΩ, as stated earlier. To get full credit, make sure you align the grounds, use the same vertical sensitivity and show the peak-to-peak voltage measurements for both channels like I am doing in the following illustrations. Before starting:

The circuits below (Figures 1, 2 and 3) are built with transformer TS_PQ4_10. The problem is TS_PQ4_10 exists in Multisim version 11.0 but has been removed from version 12 onward. However, I believe all of you (in class) are running Multisim 12 or up. You will have to replace the TS_PQ4_10 transformer of version 11.0 with the 1P2S transformer of version 12 with few tweaks.

Department of Electrical and Computer Engineering, University of Dayton, Spring 2017

Once you place the transformer 1P2S, double-click it, select the Value tab, and make these changes (see Note right underneath Figure a for further explanation): Np1 = 7.78, Ns1 = 1, Ns2 = 1, Lm = 10.0038 mH, Le = 0.146 mH, Rp = 66 mΩ, Rs1 = 0.25 mΩ, Rs2 = 0.25 mΩ. Figure a shows you how you need to connect the terminals of the 1P2S transformer so as to mimic the TS_PQ4_10 transformer.

Figure a: 1P2S setup

Note:

 Np1, Ns1, and Ns2 are respectively the number of turns in Primary coil 1, Secondary coil 1, and Secondary coil 2 in the Turns tab (select each coil and enter the appropriate value).

 Lm refers to the Constant Inductance setting in the Core tab (select Non-ideal core and enter the inductance value as 10.0038m).

 Le refers to the Symmetric leakage inductance in the Leakage inductance tab (select Symmetric leakage inductance and enter 0.146m).

 Rp, Rs1, and Rs2 are respectively the Custom resistances of Primary coil 1, Secondary coil 1, and Secondary coil 2 in the Resistance tab (select Custom resistance and enter the appropriate values).

Remember: For the rest of the Prelab, the modified 1P2S transformer of Figure a should be put in place of the TS_PQ4_10 transformer in Figures 1, 2 and 3 befow if you are using Multsim version 12 and above.

T1

7.78:1:1

Department of Electrical and Computer Engineering, University of Dayton, Spring 2017

Part 1: Full wave rectifier (with load) Connect the resistive load to the full wave rectifier circuit as shown in Figure 1. Using a dual channel

oscilloscope, observe how the output voltage waveform is affected by changes in the load resistance.

Get a screen capture of the voltage across half of the transformer secondary output and the output

voltage of rectifier for R1 = 330Ω, 7.5kΩ, and 120kΩ. It should be obvious by now that in Figure 1 below,

“XMM1” and “XMM2” are an ammeter and voltmeter respectively. In Multisim, be sure to change

“XMM1” setting from the default voltage to the ampere meter setting or your circuit will not produce

the desired results.

Figure 1 : Full wave rectifier with load

R1 = 100Ω

NB: While simulating your designs, it is okay if your numerical values (measured DC current and voltage) do not match that of the given examples below as long as the aforementioned numerical values make sense and the shape of the waveforms you get are alike the ones in the examples. See

V1 110 Vrms

60 Hz

0°

D1

1N4004GP

D2

1N4004GP

R1 T1

TS_PQ4_10

R2

50Ω

XMM1

XMM2

XSC1

Agilent

Department of Electrical and Computer Engineering, University of Dayton, Spring 2017

here that measuring 5.123 V across R1 = 100Ω and 51.231 mA (essentially) through R1 = 100 Ω makes

sense 9numerically) since (based on Ohm’s law)

.

R1 = 270Ω

You will notice that current decreases and voltage increases as the load resistance is increased. P1Q1: How and why is the output waveform affected by the load resistance? Tip: You should be able to answer by now how the load resistance affects the output. As for why, think about voltage division (between R1 and R2) as the load resistance R1 increases. P1Q2: What is the transformer ratio? Tip: The voltage between node 1 and 0 is V1 = 110Vrms and the voltage between node 2 and 0 is V2.

The transformer ratio is given by 2

1

2

1

V

V

N

N  . However, we need to make sure both V1 and V2 are the

same unit. V1 is the input voltage to the transformer whereas V2 is the output voltage to the

transformer. V1 = 110Vrms, which is equivalent to V1(peak) = 2110 Vpeak. Read V2 from Channel 1 on one of the scope captures. What you get is a peak-to-peak voltage, which divided by two gives you a peak voltage. Now you should have the proper values to calculate the transformer ratio. Part 2: Full wave rectifier with capacitive filtering Connect a capacitive filter across the load as show in Figure 2 and vary the value of the load resistor R1. Adjust the load resistor through a range of values like in Part 1 above, i.e, R1 = 330Ω, 7.5kΩ, and 120kΩ. Get a screen capture for each value of load resistance used.

Department of Electrical and Computer Engineering, University of Dayton, Spring 2017

Figure 2: Full wave rectifier circuit with capacitive filter

R1 = 100Ω

R1 = 270Ω

V1 110 Vrms

60 Hz

0°

D1

1N4004GP

D2

1N4004GP

C1 33µF R1T1

TS_PQ4_10

R2

50Ω

XMM1

XMM2

XSC1

Agilent

Department of Electrical and Computer Engineering, University of Dayton, Spring 2017

P2Q1: What is the effect of incorporating a capacitive filtering? Tip: Using the capacitor makes the circuit a peak detector circuit (recall Lab 2). Part 3: Full wave rectifier cascaded with filter and a voltage regulator

Connect a Zener voltage regulator circuit as shown in Figure 3 to the output of the full wave rectifier

circuit. The diode D3 is a 10.05 V zener diode. In Multisim, use the 1N4740A zener diode. Adjust the

load resistor through a range of values like in Part 1 and Part 2 above, i.e, R1 = 330Ω, 7.5kΩ, and 120kΩ.

Get a screen capture for each value of load resistance used.

Figure 3:Full wave rectifier with filter, voltage regulator and load

R1 = 100Ω

V1 110 Vrms 60 Hz 0°

D1

1N4004GP

D2

1N4004GP

D3

10.05 V

C1 33µF R1

T1

TS_PQ4_10

R2

50Ω

XMM1

XMM2

XSC1

Agilent

Department of Electrical and Computer Engineering, University of Dayton, Spring 2017

R1 = 270Ω

P3Q1: What is the effect of the additional subsystem? Tip: A Zener diode can be used as a voltage regulator. When the “Zener knee voltage” is reached, the voltage across the diode remains approximately constant even if current is increased (recall Lab 1).