Introduction What is MoHAT? Is MoHAT for me? Screen layout

Begin a new simulation

Open/Save simulations

Make a circuit look right

Add graphs

Run a simulation

State variables

Miscellaneous options

Advanced features

Introduction

What is MoHAT?

MoHAT is a circuit simulation tool that demonstrates the interaction of Diodes, Mosfets, and BJTs within any given circuit. Each of these three elements have different states associated with them that determine how they behave. MoHAT takes a PSpice .out file as input and displays the circuit described by that file. It then steps through the data that was calculated using either a transient analysis, DC sweep, or AC sweep. As it steps through the data, it changes the colors of all the Diodes, Mosfets, and BJTs within the circuit to show their state at that instantaneous point in time.

The benefit of such a display is to easily show how the elements change with respect to each other; all you have to notice is the color. At any point, the simulation can be stopped or slowed down to manually step through each point and see what changes.

Is MoHAT for me?

Read the "What is MoHAT" section above, and if you aren't completely lost, or completely bored, then MoHAT just might be what you're looking for. MoHAT is most useful for students just beginning to do analysis on circuits containing diodes, mosfets, and BJTs. At this critical juncture, students must try to understand, for example, that BJTs function in one of four different ways at any given time and that increasing the input by the slightest amount could cause a diode to turn on, which causes a BJT to switch states, causing a mosfet to become saturated, making the output spike. This relationship between elements is very difficult to comprehend, making students feel stupid and frustrated. This material is usually taught by taking a circuit at a specific input value and then tracing through the circuit to determine first by guessing then by analyzing the state for each element. This quickly becomes tedious and overwhelming, since a wrong guess doubles the work. Once you do finally finish, you only know the states of the elements at that single input.

If you are in this situation and understand the agony, then try MoHAT. As an engineer, circuit analysis techniques will always be a required skill, so use MoHAT today to make the learning last forever.

Screen layout

If this is your first visit to MoHAT, let me give you a quick tour of the screen. On the upper left, beneath the logo, lies the simulation controls that allow you to start and stop the simulation and change other such options. Below that is the control menu. Any link you click on within this menu will open up a dialog box with options ranging from entering your data to viewing the credits page. On the bottom of the page is a text box that shows the circuit listing for the currently displayed circuit. Directly above that text box is the options menu, which has options to manipulate your view of the circuit. The buttons on the left side of the menu control what happens when you click on individual elements, and the buttons on the right change things like the zoom ratio and allow printing. Above the options menu and to the right of the control menu is a big white box containing the main viewing area where the circuit is displayed.