How To Create A Circuit In Multisim

First: The circuit

In the figure below, we have a current controlled battery charger circuit using LM317. This circuit is usually used for a Lead-acid 12V battery.

Step – 1

Once you open Multisim, the first thing is to add the components. For that, you can either go to Edit tab -> Component or press ctrl+w.

The "Select a Component" window will open. You can type the Component that you want or go to the Group dropdown menu. The figure below shows the essential information about this window. There will be different versions of the same Component. You should pay attention to the footprint, as you are going to use it in your layout.

To place the Component, select the one that you want and click Ok. The window will close, and the Component will be placed wherever you left-click in the schematic area. Now, repeat the process with all the other components from the schematic.

We will also need to connect the power connector and a two-pin terminal block for the battery. The power connector is PJ-007, and the terminal block is 282834-2.

Step – 2

Now that you have all the components, you can change their position by selecting the Component and dragging the Component. To rotate it, you can use the ctrl+r shortcut. You should have something like the figure below:

To make the connection, you just need to click on the pins of the two components you want to connect. Once you click on the first pin, you see that the mouse icon changes, and a trace appears following the mouse. You now should have something similar to the following:

Step- 3

You can´t simulate it as it is. We need to add the power and ground. Go to Select a component window and add VCC and Ground. You will find it under the Source group-> Power_source.

Connect the power and the ground as it shows in the figure below:

Note that VCC shows 5.0V. We can change it by right-clicking it and going to Properties. There you can set 19v (as the battery needs at least 12.7v to charge).

In order to verify the voltage in J2 (the battery connector), we will need to place a voltage meter in it. You will find it under Simulate tab -> Instruments -> Multimeter.

Drag the multimeter and connect its pinouts into the J2 connector.

Step 4

Now to simulate, you can click F5 or go to the tab Simulate -> Run.

After that, you double click the multimeter icon, and it will appear in a small window. You can select the information you want to see by clicking the symbols: A for current, V for voltage, Ω for resistance, and dB for the Decibels to measures decibel voltage loss between two nodes in a circuit.

As you can see, the voltage in the battery terminal is 13.8V, the right lead-acid battery charging voltage.

If you want to see the multimeter specs, you can click on "set." A small window will appear with all the internal parameters of a multimeter.

Step - 5

Commonly, some components that we use in the schematic do not have a footprint (or it was not chosen when it was selected). For example, the capacitor that we are using in this design does not have a footprint. To add or chose a footprint, you need to right-click the Component and go to Properties. Once the Properties window opens, you should go to the Value tab -> Edit footprint -> Select from Database. You then can choose the footprint that matches the device that you are going to use.

Once all the electric comments have a footprint, their colors will change from black to blue. The connectors will be from black to green.

Step -6

Now that you have your circuit working and you are happy with the results that you got, you can now start building your PCB from your recently created schematic. To do that, you have to save your file and click on Transfer -> Transfer to Ultiboard -> Transfer to Ultiboard.

A window will appear to import your netlist. You can just click ok.

Step -7

Now you will be in Ultiboard. The window that you are seen is the layout window. On your right side, you can see all the layers that your board has. However, you still did not put anything on the board. The yellow square is your board edge, and on top of your yellow square, it is your components.

To start populating your PCB, you should left-click on your Component and drag it inside your yellow square. You can rotate your components using the same command as in the Multisim: ctrl+r or right-clicking at it and going to the Orientation tab.

Step-8

After you place your components, you can click the AutoRoute tab -> Start autorouter. It will route the traces automatically.

Step-9

As our PCB will handle up to 400mA, we should change our traces width. You can set the width of your traces in PCB Design rules under the Options tab. However, it will be applied only for the next time that you open the software. To change the traces width in your design that is already open, you have to go on "Net" tab on your screen's bottom.

It will appear a spreadsheet with all the information of the traces. There, you can change the width by just typing the width that you want. In our PCB, we have changed it to 50mil.