Glossary

You can read this section starting from the beginning and reading to the end. If you get to the end and understand everything then you will be able to read any section of this manual and understand it well.

Terminology	Definition
Amplitude	The amplitude is shown by DAQ Plot in its signal viewer, spectrum view and at other locations. In a basic setup, the Amplitude is the voltage collected from a piece of hardware and the amplitude index if the channel index of the hardware device. In more complex settings the amplitude is the result of several different data mappings using the Derived and Data preferences. The derived preferences can map a channel to arbitrary amplitude index, or combine channels to one amplitude, so the relationship from channel to amplitude need not be straightforward.
Channel	Each input source has one to sixteen channels of data. Those channels can be mapped in various ways to amplitudes (see Amplitudes). By default, there is no mapping so that initially the amplitude index is the channel index (a one to one correspondence) of a device.
Electron	An electron is a very small piece of material, so small that it can not be seen directly. Electrons are everywhere and are flowing through your body all the time and help your brain think and your heart beat as well as perform other useful functions.
Battery	A battery is a device that stores electrons and will release those electrons when you attach it to something like a flash light.
Electricity	When electrons move then that movement is called electricity. It is also called electricity when electrons don't move but rather push against something in order to move.
Voltage	Voltage is the amount that electrons push against something. The more those electrons push, the more voltage they have. Now you know why high voltage wires are labeled as dangerous! If those electrons push hard enough they can go right through your body, and make a nasty burning hole while doing it! Ouch! Notice that the electrons don't have to move to have voltage, they just have to push hard.
Current	Current is the amount of electrons passing through something at any point in time. To have current, the electrons need to move. If presented with an obstacle those electrons may not be able to move unless those electrons have a high enough voltage. So, to have useful electricity you need to have electrons with a high enough voltage and a high enough current.
Circuit	A circuit is a connection of wires that form a path through which electrons can flow. If that path is broken then the circuit is called broken, and is, in fact, no circuit at all.
Wire	A wire is a long thin piece of material, usually metal, that can be used to allow electrons to go from one piece of a circuit to another.
Dielectric	A dielectric is a material that resists the flow of electrons. If electrons push hard enough then they will flow through any material, but dielectrics are materials that do not permit electrons through unless those electrons push very hard. Usually if electrons flow through a dielectric those electrons push so hard that they break the dielectric apart in an explosion or fire.
Conductor	A conductor is a material that lets electrons go through it easily. Copper, aluminum, steel, and most other metals are good conductors.
Resistor	All materials resist electrons flowing through it. Electrons have a hard time getting through some materials, while with other materials electrons move freely. A resistor is a material that lets electrons pass with some difficulty, but not too much. Electrons are only subject to a resistor for as long as they are in the resistor. The longer electrons flow through the resistor, the more the resistor has the opportunity to resist the electron.
Potential	Potential is voltage. Usually potential is referred to as "electrical potential" to distinguish it from other potentials, like your potential to graduate school.
Rheostat	A Rheostat is a device that can change resistance. You can buy a rheostat at an electronics shop like Radio Shack. I used one called a Audio Taper/1Meg Ohm potentiometer. When you buy your rheostat it will most likely be encased in a small metal cylinder. It doesn't look like a long wire at all. That is because that long wire is wrapped around a piece of plastic shaped like a donut which is then placed in the metal cylinder. After you have had a good time with your own rheostat I would suggest prying the rheostat apart and unwinding the wire if you can. The wire on a rheostat is usually glued to the piece of plastic, so it may be hard to take apart. When I was a kid I took everything apart. Sometimes I put them back together again too. Remember: If you can't take it apart then you can always cut it in half.
Potentiometer	A Potentiometer is a rheostat. When a potentiometer is placed on a circuit board it is many times referred to as a pot. I don't like the term potentiometer because it refers to a meter that measures the electrical potential of a circuit. A rheostat varies resistance, while a meter measures it. One "observes" while the other one "performs". This issue is common in electronics because many basic electrical devices were discovered and successfully used before they were fully understood so they were never really named right in the first place.
Terminal	A terminal is a piece of a device where you can attach a wire, for example by soldering it, wrapping it, or screwing it to the terminal.
Signal	A signal is a sequence of values, in this case voltage, measured over time and displayed as a curve.
Strip Chart	A strip chart is the paper output of a device with a pen or series of pens that write onto a scroll of paper as the paper moves under the pens while the pens apply pressure to the paper and hence write on the paper. Each pen move back and forth on a lever independently to produce a curve for each pen. The movement of the pen is proportional to the voltage applied to its solenoid. As such, the horizontal axis has units of uniform time and the tangential axis is in units of voltage. Such a device is called a strip chart recorder. That is a metaphor for more modern systems such as DAQ Plot that show signals in a similar form. DAQ Plot could have been called "Strip chart Recorder" except that DAQ Plot also has a built-in spectrum analyzer, feedback control loops, output channels and many other things. In addition, DAQ Plot embeds device drivers and other machinery necessary for its operation.
Thomas Edison	Thomas Edison was not the guy who invented the light bulb, nor did he invent electricity. He did tinker a lot and was also a fairly shrewd business person.