Introduction

Begin a new simulation

Open/Save simulations

Make a circuit look right Why doesn't it look right? MoHAT functions Adjusting elements manually Connecting elements Zooming

Add graphs

Run a simulation

State variables

Miscellaneous options

Advanced features

Make a circuit "look right"

Why doesn't my circuit look right?

When MoHAT opens up a new simulation, the only information it has on your circuit is the textual circuit description used by PSpice. Due to the complexity circuits can reach and the vast difference in general layouts, there is no way for MoHAT to "know" what you want the circuit to look like. The first version of MoHAT attempted to guess what the circuit should look like, but the resulting circuit was often too cluttered to make sense. Finally, it was decided that when a new simulation was loaded, MoHAT would simply lay out the elements in a grid pattern, so that each element could be quickly located and placed in its proper spot.

Some functions to help you position the elements

As stated above, MoHAT can only guess as to what you want the circuit to look like, but it does have some functions to help you. To access these functions, click the Positioning link in the MoHAT controls menu. When the window opens, you will see four main sections with different options to control how the elements are sorted.

The upper-left section lets you select two radio buttons indicating the order you followed when inputting the circuit in PSpice. Again, this is just a general order to help MoHAT know the general location of each element. The section below lets you choose to order the elements by row or column. The default is to Fill by column with 3 columns. With this option set, the elements would be placed in three columns, filling as many rows as necessary to place all the elements. The Fill by row option does exactly the opposite in that it begins to fill the specified number of rows using as many columns as required. The Spacing section determines how close the elements are placed next to each other. Try different selections to see which works best. The last section has an option to fill in all the elements in reverse order. Check or un-check this option depending on how you entered your data.

When all your options are selected, press the Elements button at the bottom of the window to order your elements. You will notice that none of the nodes are affected by this ordering since their position is arbitrary. Pressing the Nodes button will cause each node to be placed in the center point calculated from all the elements connecting to it. These functions aren't meant to make your circuit look perfect, but rather to help you get started.

Adjusting the elements manually

To make your circuit look just right, you will need to adjust each element by hand. Located on the left side of the options menu are four buttons designed to make this process quick and easy. These buttons from left to right are move, rotate, flip vertically, and flip horizontally. These buttons work much like a toolbar in other programs. You select what you want to do to an element and click the appropriate button in the options menu. Then, whatever element or node you click on will change according to what's selected below. For example, if you highlight the rotate button, then any element you click on will be rotated 90 degrees counterclockwise. When the move button is selected, pressing on an element causes it to follow the cursor until you release the mouse button. For a quick visual reference, whenever you roll over an element, the cursor changes to indicate the selected tool.

As you move elements around, you may notice that they snap into place. To help you line the elements up, you can display a grid on the screen by pressing the Show grid button located in the bottom right corner of the circuit viewing area. To move multiple elements at once, draw a rectangle around the elements you wish to move, and a colored box should appear covering the elements. Clicking and dragging that colored box moves the elements that lie within the box. When you release the mouse, the box will disappear leaving the elements in a new location.

Connecting elements together with lines

Once your circuit is in place with every element and node in its correct locations, you will want to connect the elements together. To connect your elements together, press the Connect elements button located on the right side of the options menu. Making certain assumptions and using an A* search algorithm, MoHAT will now draw lines connecting the elements. It works by looping through all the nodes and trying to find the best path from the node to each element connected to it. The Drawing options link in the control menu has a few options that affect how the elements are connected. The first two options determine whether or not power and ground nodes are drawn. The third option allows the lines for each node to be drawn in either black (unchecked) or a random color (checked). To have the changes take affect, press the Connect elements button, and the circuit will be redrawn. Anytime you adjust the position or rotation of elements, the lines will disappear until you press the Connect elements button again to recalculate the lines.

Zooming

The last step in manipulating the look of the circuit is to make sure that your circuit fully utilizes the size of the circuit viewing area. To do this, there are three buttons that affect the zooming of the circuit. The two most common ones, which look like magnifying glasses, are located in the options menu, and they simply zoom in or out by 15%. The third option is directly to the left of the magnifying glasses and is labeled Fill screen with circuit. This will zoom in and scroll until your circuit fills up the circuit viewing area and is centered.