The Edit Plot List dialog consists of three tables. The table on the left shows the hierarchy for the case of multilevel signals. In the middle table (Signal Name List) you see a list of the available signals for plotting. The table on the right (Graph Name List) lists the signals to be plotted. Select one of more signals from the middle table and use the right arrow "Add-->" button to move them to the right table. You can also select more than one signal using the "Ctrl" key or a range of consecutive signals using the "Shift" key. You may modify and revise the list of the signals to be plotted by moving one or more items from the right table back to the middle table using the left arrow "<--Remove" button.
Besides voltages, currents and powers, [[B2.Spice A/D]] allows you to define, calculate and graph or tabulate new custom plots. This is done using the two buttons labeled "Add Custom Plot" and "Edit Custom Plot". Both buttons open up the "Edit Signal Plot" dialog. Here you enter a name and color for your new plot. The dialog has three tables. On the left you see a list of all the available signal names. In the middle, you see a list of all the legitimate legal mathematical functions. On the right is a list of all the legitimate mathematical operationslegal operators. You can define your new plot using a mathematical expression involving the available signals and the legitimate mathematical functions and operations.
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==Using Probes as Observables==
A simpler way of defining voltage and current observables is using "Probes". [[B2.Spice A/D]] provides two types of probes: Voltage Probes and Current Probes. Both can be accessed from the [[Schematic toolbar|Schematic Toolbar]] at the top of the screen or by selecting "Probe Mode" in the [[Schematic Editor]]'s Edit Menu. The keyboard shortcut "Ctrl+P" can be used for this purpose, too. While in the Probe Mode, you can place as many probes as you want. Voltage probes must be placed at the circuit nodes or on the wires, while current probes must be placed on a device pin. Voltage signal are always measured with respect to the circuit's ground. The direction of a current signal is determined by its underlying device pin, which shows the current's entrance into the device. The opposite figure shows a typical operational amplifier (Op-Amp) circuit with two voltage probes placed at its input and output nodes. The figure below it shows a graph of the plotted probe voltages. Â A great advantage of using probe as observables is you can easily move them around and placed them on different nodes or pins. The graphs or tables then get updated automatically without having to run the test once again.
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[[File:b2MAN_Fig113.png|thumb|200px160px|B2.Spice's Probe menu.]]
==Plotting Complex-Valued Signals==
In AC sweep [[tests]] and other AC-types [[tests]] such as network analysis, the simulation output data are complex-valued. In this case, you have to specify whether you want to plot the magnitude or phase of a signal or its real or imaginary parts. In the case of magnitude, you have to specify whether to use dB or linear scale.
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