“What is the best free circuit simulation software?” The answer is here. As a solid user of this circuit simulation software, I introduce this to you; LTSpice. “How to Use LTSpice?” “How to Start Simulation in LTSpice?” So many questions in mind, we will answer all these. In this article I will teach LTspice circuit simulation tutorials for beginners. Advanced topics will be discussed in another article.
LTSpice is a freeware electronics circuit simulator developed by Linear Technology. This is a perfect fit for students or anyone that wants to start learning circuit simulation. You can download it from the internet anytime you want. In this tutorial, I assume that you already have the software.
LTSpice Circuit Simulation Tutorials for Beginners
In this topic I will discuss “How to Do a Simple Circuit Simulation using LTSpice”. Our circuit model is shown in Figure 1. The analysis to be performed is transient with a stop time of 10msec and the DC supply voltage must start at zero. The circuit to be build is shown in Figure 1.
Here it goes.
Step 1: Open LTSpice software
Figure 2 will show up.
Step 2: Start a new schematic by clicking the icon as Figure 3 illustrated.
After executing Figure 3, the appearance of the window changes as below
You can notice now the appearance of the icons and additional tabs in the heading section of the window.
Step 3: Placing components to the new schematic page
There are several ways to do this, first you can navigate to Edit then click resistor and capacitor symbols. The second method is to click the icon labeled “Component” in the header as Figure 5.
Another method is by directly get it from the header section as shown in Figure 6.
The last method is through the short cut keys. You can type “R” for resistor, “C” for capacitors and “G” for ground.
We will use the second method to get components since it will display the entire components category. After following the direction of Figure 5, Figure 7 will show
We will click “res” then click “OK” to get resistor and click anywhere in the schematic to place the component. Click “cap” to get a capacitor and follow the process. Double click the components will work as well. We are going to use 4 resistors so you can repeat the process four times (though there is a copy and past option also).
Now we will get a voltage source and a ground. Double click on voltage and click anywhere in the schematic to land it. For the ground, just type “G” on the schematic and click anywhere to have it.
The new schematic looks like in Figure 8 after the placing the needed parts. We will start rearranging the circuit to build the target circuit.
Step 4: Rearranging and wiring the components
To rearrange components, click on the small hand icon in the toolbar section in the header of the schematic page or just follow Figure 9. After doing so, the mouse cursor will change from a cross shape to a small hand. When you left click on any components, you can move it to any part of the schematic. When you are in the desired location to drop the part just left click again to land the component.
To rotate part, left click on the device with the mouse cursor is hand type then click CTRL+R then left click. To mirror a device, press CTRL+E then left click.
To connect the components, click on the pencil icon in the toolbar section of the header of the schematic as Figure 10 shown. Right after, the mouse cursor will change to a big cross. Start the connection by left clicking into the box of the component terminals.
After wiring the components, the circuit is now looking like Figure 11. Now we are going to rename devices according to our target circuit.
Step 5: Renaming parts, changing values and adding a net name
To rename a component circuit code, just hover the mouse on the part that you want to rename and right click until a window like in Figure 12 appears. Type the name you want on the area provided. Just remember, space is not accepted.
To change device value, just hover the mouse on the existing device value and right click until a new window will appear as Figure 13.
For “kilo” notation, you can use k. You can use “m” for milli, “u” for micro, “n” for nano and “p” for pico. To add a net name, just follow Figure 14. Remember space is not accepted here.
After all the modifications, the circuit will now look the same with the target circuit as Figure 15. We are now ready for the simulation.
Step 6: Setup the simulation command
The target simulation is transient with a 10msec stop time and all DC sources must start from 0V. Now, click on the “Simulate” tab and then “Edit Simulation Command” as shown in Figure 16.
Right after, a new window will show up as Figure 17. Click on “Transient” tab. Put 10m under “Stop Time” for 10msec target stop time. Then click “Start external DC supply voltages at 0V:”. Then click OK and left click on the schematic to drop the simulation command.
After doing so, the final circuit is look like below figure.
Step 7: Running the simulation
Click on the run icon as described in Figure 19 to start the simulation.
Right after, another window will appear as Figure 20 . This is the waveform window. To display a waveform, let’s say we want to see the output, just hover the mouse in the Vout net until a probe like object appear then left click. Figure 21 displays the final outcome of the simulation. To save the schematic, navigate to “File” then “Save As” to the location you want.