The first thing you need to do is create a new circuit and editor. Pull down the File menu and select New. A dialog box will appear. Type in any name you like for your circuit and hit return(enter) or click on OK. Give it a few seconds as a lot needs to be done and it takes a while over the network (including loading images).

The circuit we will draw and eventually simulate looks like:

so lets get started.

You will see a large drawing area and a toolbar full of logic elements. Click on the OR gate. A dialog box will appear that will allow you to customize the gate. The gate we want is the default case (2 inputs, one gate, facing right), so simply click on OK.

The symbol for the OR gate should now appear, outlined in pink. It will follow the movement of the mouse, so move it to the center of the drawing area and left click to place it (right clicking will cancel the creation of the gate). Notice that when you are placing the gate there is a message with a yellow background in the upper left of the window that guides you. You can check this at any time if you are unsure what to do next or what "state" the circuit editor is in.

Once you've placed the gate, move the cursor around the window. Note that whenever you move the cursor over the gate its bounding box becomes visible. Move the cursor over the gate, press and hold the left mouse button, and drag the gate around the screen. Releasing the mouse button will place the gate at its current location.

Next select a NOT gate, say OK to the default characteristics, and get ready to place it. You have a couple of options. You can place it near the OR gate and then create a wire to connect it to the OR gate. Alternatively you can move the output of the NOT gate so that it touches one of the inputs of the OR gate - this will automatically connect them. We'll automatically connect them right now and draw wires later.

Drag the NOT gate so that its output touches the lower input of the OR gate. Notice that the output/input become green when they touch. This means that a connection is possible. Many connections are not possible (e.g., connecting the outputs of two gates) and if you try to make one you won't get a green. Once you get a green, left click to place the NOT gate and automatically connect it to the OR gate.

If you'd now like the NOT gate to be a little farther away from the OR gate, just move the cursor over it, press and old the left mouse button, and drag the NOT gate wherever you want it. Notice that there is a wire connecting the two gates that follows the NOT gate as you drag it around.

At this point we have all the gates we need for the boolean expression. The unattached input of the OR gate is A and the input of the NOT gate is B. Lets test it by connecting constant values (0's or 1's) to the inputs.

We'll first place and connect two elements that generate constant values in our circuit. Pick the image from the toolbar that is a small rectangle with the letter N inside and a line sticking out the right end. You'll get a dialog box in which you can set the constant value, and there are two ways to do it. One is to type the value into the box indicated. The other is to click on the black triangle and get a keypad that you can click in the digits of the value. Try both if you like. Click OK when you have picked a value (0 or 1) and place the element a couple of inches to the left of the NOT gate (don't connect it automatically). This time we will connect it by drawing a wire.

Move the cursor into an open area and right click. A menu will pop up - select wire(s). When you do, the menu will disappear and a small circle will appear. This is the beginning of a wire. Move the cursor (and the circle) over the output circle of the constant element you just placed. When it turns green, left click and then move the cursor to draw the other end of the wire. We'll make this a segmented wire (just for demonstration purposes) for now. Drag the new end of the wire someplace and left click. Drag again and left click several times to draw a wire with lots of segments. Don't worry about neatness. Finally drag the new end to the input of the NOT gate and left click again. This will complete the wire connecting the constant generator and the NOT gate.

The wire you just drew probably wanders all over the place. Lets clean it up. Drag the cursor over any part of the wire (avoid corners for now). Notice that that part of the wire turns pink when the cursor is over it - that how you know the editor is selecting it. Select some middle segment of your wire and right click. Pick delete from the menu that appears and watch that segment of the wire disappear. If you move the cursor onto a corner of your wire a little pink circle will appear. If you right click at this time and choose delete you'll remove the corner and both line segments connected at that point. Keep deleting parts of your wire until there is little (but not nothing) left. Then grab a dangling end of your wire and drag it onto another dangling end (or onto a gate input or output). Release the mouse button to re-connect.

Now create another constant element and connect it to the free input of the OR gate. Finally, begin a wire at the output of the OR gate. Draw a single wire segment a couple of inches long to the right, left click to place the corner, and then right click to stop drawing wire segments. Be sure to left click before right clicking.

We now have a complete circuit that we can test with the given input values. To test it, pull down the Simulator menu and pick Run. This will run the simulator on your circuit.

The simulator runs as long as some value could possibly change in the circuit. Once no more changes are possible, the simulator stops. At this point the color of a wire is black if it has zero on it, red if it is a one (or more correctly, non-zero - this applies to wire "bundles", which is a single "line" that represents several wires bundled together).

The values on the wires obviously depend on the values of the constant value elements you chose for your circuit, so verify that the wire values are right. You can also move the cursor over a wire and see the current value in the cyan message bar above the circuit.

All gates have a built-in propagation delay that are used during simulation (wires have no delay). It can be interesting to see the time history of each signal as it propagates through the circuit. An interesting case is when A (the upper input to the OR gate) is 0 and B (the input to the NOT gate) is 1. This will cause the output of the OR gate to temporarily have the wrong value as the 1 propagates through the NOT gate and then the OR gate.

Lets make the inputs have the right values (if they already do, then just follow along anyway). Right click on the constant generating element for the upper OR input. One way to change the value is to either cut or delete the element and create a new one with the value 0. The other way (try this way) is to select the modify menu option. This will pop up a dialog box in which you can change the value. Make the value be 0 and click OK. Now make the input to the NOT gate be 1 by whatever technique you choose.

To see the time history of the value on a wire you must attach a "probe" to the wire. Move the cursor onto the output wire, right click, and select the Attach Probe option. A dialog box will appear so you can give a name to the probe. Type in something descriptive, like "output". When done you'll see the name you typed in blue above the wire, thereby indicating that a probe is now connected. Your circuit should now look like this:

Now pull down the Simulator menu and select Show. The bottom of the window will now show simulator controls. Put the cursor on the divider between the simulator controls and the circuit editing window and drag it up to show more of the simulator. Below the buttons will appear an area where signal traces will appear when the simulator is run again. Show about an inch or so of this white trace area, then click on the Restart button. This will re-initialize the circuit and run the simulator again. You should now see a trace of the output wire, and in particular see that it started at 0, became 1 for a short time, and then went back to 0, which is the correct final value for this circuit. Move the mouse over the trace to see the exact timing of each signal change.

It is often handy to be able to run the simulator for a little while, stop, start again for a little while, etc. To do this, click on Step now. The simulator will run for one unit of time (you can assume this unit to be whatever you like - a nanosecond, picosecond). Each click on the button will run the simulator for another time unit. If this is too slow, change the value in the Step box at the top right of the simulator window. Then each click of the button will run the simulator for that length of time.

Lets change the propagation delays of the two gates in the circuit. Move the cursor over one of them and right click. Pick Change Timing, put a new value in the value box, and click OK. Change the other gate's propagation delay similarly.

To run the simulator with these new values, first make sure that the previous simulation was done. If you had stepped it for a while but not to the end, click on the Stop button. Now either Restart the simulator, or Step through it and observe the signal trace.