Md. Sihab Talukdar
Mst. Najnin Sultana
Proteus is one of the most famous simulators. It can be used to simulate almost every circuit on electrical fields. It is easy to use because of the GUI interface that is very similar to the real Prototype board. Moreover, it can be used to design Print Circuit Board (PCB).
1. Introduce students on using proteus software.
2. Introduce how to run simulation of designed digital circuit.
3. Understand how to applied digital logic equation to real hardware designs.
Tools and equipment specifications
Proteus has many features to generate both analogue and digital result. However, this lab will focus on only tools that will be used in digital schematic designs.
Figure 1: Example of Proteus software window.
Proteus that will be used in this lab is version 7.1, can be called from Start>>Program>>Proteus 7 Professional>>ISIS 7 professional.
Proteus has many models of electronic equipments such as logic gates, many kinds of switches and basic electronic devices.
These equipments can be founded by clicking on symbol of device and then press "P" . Then, a new window will pop up and wait for the part’s information as shown in the Figure 2 .
Figure 2 : Example of pick device page(1)
1. Type information of the device such as “and gate” in the box 1.
2. If some specific category is known, the device can narrow on focusing by selecting catalogue in the box 2.
3. After the information is put, the list of the related devices will appear in the box 3, so that needed device can be choose here and then click “OK” button to confirm the selection as shown in Figure 3.
Figure 3: Example of picking device page(2)
Power Supply and input signal generator
All of the electrical circuits require power supplies. The power supplies for logic gates are represented in the digital system design on proteus because the schematic may be too complicated to understand for simulation section. Therefore, the power supplies will be needed as input power for a system. Moreover, all of the input generators, such as ac, dc, and pulse, are contained in this category and it will be shown when symbol of "AC" are clicked.
In addition, “Ground” will not be contained in this groups, because it is not input signal but it is just a terminal junction. Therefore it will be grouped in the terminal category as shown in Figure 5 .
Figure 4 Figure 5
In addition, there is another input that usually be used in digital circuit designed system but it does not exist in real world as an equipment. It is called as “LOGIC STATE”. It can be found in picking part section (typing “logicstate” and pick it.)
Figure 6: Logic state
How to do the simulation?
Selecting all devices needed to be placed on the circuit sheet (Grey sheet) and wiring it, can be done by following these steps:
1. Click on "input button" and select a first device that will be placed.
2. Place mouse to wherever the device is preferred to be placed, and then click the left button of the mouse. The device will be placed. If it is needed to be moved, Click the right button of the mouse on the device symbol to select the part and then hold the left button of the mouse and move the symbol to wherever it is needed to be placed.
Figure 7: Placing the parts
3. To wire devices together, click at the source pin of the device and then move mouse cursor to the destination pin of the device. In this step the pink line will be appeared and it will be the wire of the circuit after clicking mouse on the destination pin of the circuit (as shown in figure 8 ).
Figure 8:Wiring devices together
4. After wiring all devices and all inputs together, the simulation is ready to be run by clicking on "play button" to run and "stop button" to stop.
Actually, the digital result on proteus can be seen in small square at the pin of the equipments and the state will be shown in 4 colors (red = logic “1”, Blue = logic ”0”, Grey = Unreadable logic and Yellow = Logic congestion).
Connect the following circuit on PROTEUS and then simulate it; after that find the truth table using PROTEUS program, also find the truth table manually and then compare the two results together:
a) Manually the truth table will be as the following:
A B C G
0 0 0 1
0 0 1 0
0 1 0 0
0 1 1 1
1 0 0 1
1 0 1 0
1 1 0 0
1 1 1 0
b) Using PROTEUS the truth table will be as the following:
c) We note that the results are identical for both the manual and PROTEUS.
Follow the procedure used in the previous example, solve the following example, and then show the result to your Lab Instructor.