Create your first circuit simulation

There are some basic steps that will get you started in using Caspoc. In this tutorial we will create a simple resistance circuit and measure voltages and currents. Although this looks vairly simple, it shows you some basic steps in Caspoc.

We start with opening Caspoc from the start menu. You will see the white work-screen where we will place the components and on the left side the Project Manager from where we will select components. From the Project Manager we will not only select our components, but we can also start tools and read data from it.

On the top of the window you see the menu items as well as many buttons. These buttons are shortcuts to the command that you can select from the menu.

In this tutorial we will create a resistive circuit and therefore we select our components from the Project Manageron the left side. Click on the [+] sign in front of Components or double click the item Components

The component group will open in the Project Manager and list three sub groups:

• Circuit
• Blocks
• Library

Circuit
From the item Components/Circuit we will select all components that have to do with physical components, for example resistors, inductors, semiconductors, etc. Blocks
From the item Components/Blocks we will select all components that have to do with signals and mathematical relations, for example addition, sinusoidal signals, integrators, etc. Library
From the item Components/Library we will select all components that have to do with a combination of physical components and signals or mathematical relations, for example electrical machines, PI controller, harmonics calculation, etc.

In our first simulation we will create a circuit from a voltage source and a resistor. In the Project Manager open the item Components/Circuit

It shows you an overview of the categories that contain circuit components. We will first place a voltage source on the work-screen. To do so, select the item Components/Circuit/Sources You see a list of sources that can be used in your circuit. Since we need a voltage source, we select the component V. You select a component and place it on the screen using the following steps:

1. Move the mouse pointer over the component to be selected, in our case the voltage source V
2. Click and release the left mouse button, while the mouse pointer is positioned over the component. It is important to release the mouse button, the component is now sticked to your mouse pointer
3. Drag the mouse pointer over your work-screen to the place where you want the voltage source to be placed.
4. During dragging you will see that the voltage source is sticked to your mouse pointer
5. (Try to click the right mouse pointer during dragging of the component over the work-screen, you will see that the component is rotating)
6. To place the component, click and release the left mouse button. The component will be dropped onto the work-screen.

At the moment that you click the left mouse button to place the component on the empty work-screen a message box pops-up. It askes you to automatically include a ground node. Just click the [YES] button to automatically insert a ground node. The voltage on this ground node will always be zero volt. The voltage source is now placed on your work-screen. The next step is to add the resistor. You will find the resistor in the item Components/Circuit/RLC You see a list of pasive components that can be used in your circuit. Since we need a resistor, we select the component R. You select the resistor and place it on the screen using the following steps:

1. Move the mouse pointer over the component to be selected, in our case the resistor R
2. Click and release the left mouse button, while the mouse pointer is positioned over the component. It is important to release the mouse button, the component is now sticked to your mouse pointer
3. Drag the mouse pointer over your work-screen to the place where you want the resistor to be placed.
4. During dragging you will see that the resistor is sticked to your mouse pointer
5. (Try to click the right mouse pointer during dragging of the component over the work-screen, you will see that the component is rotating)
6. To place the component, click and release the left mouse button. The component will be dropped onto the work-screen.

Both components are now placed on the work-screen and we have to connect them. Connections are made by drawing wires between the nodes of the components. The drawing of a wire is started by clicking and releasing the node with the left mouse button. Drag the mouse pointer to the end node and click and release the mouse pointer to connect the wire. Since we would like to know the current through the resistor we have to add a scope to the work-screen, by clicking he first button on the button bar at the bottom of your window. To display a current through a circuit component, click with the left mouse button over the input of the Scope, drag the mouse and release the left mouse button over the circuit component. A dashed line indicates the connection. The scope is now inserted in our circuit and the dashed line indicates that hte current throught the resistor will be shown in the scope Start the simulation by pressing the Play button or pressing the [Enter] key. The simulation is now started and in the scope the calculated current will be shown. To have closer look at the simulation results, open the scope by clicking it with the right mouse button. The scope will open and will show the current through the component. If you used the standard default values for the voltage source and the resistor, the simulated current will be 10V/1000ohm=10mA.

Next we will change the value of the resistor and see what the new current will be. You can edit all components by clicking them with the right mouse button. A component properties dialog box will pop up, where you can change the name of the component and its value. In his dialog box you can also set the color of the component, rotate the component or add some remarks to this particular component. Right click the resistor with your mouse pointer and the properties dialog box will pop up. The second input field is the value of the resistor. Its default value was 1000 ohm and we will change it into 2 ohm. Change the value of 1000 into 2: Close the component properties dialog box by clicking [OK]. The value of the resistor is now changed into 2 ohm. Restart the simulation by pressing the Play button or continue the simulation by pressing the [Enter] key. The simulation is now running and in the scope the calculated current will be shown. When the simulation is finished, the results in the scope will be rescaled automatically. It will show the new current of 10V / 2 ohm = 5 Ampere.