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--- 184_notes:defining_current [2020/08/23 19:20] – dmcpadden
+++ 184_notes:defining_current [2021/02/23 20:31] (current) – [Conventional Current] bartonmo
@@ Line 10: / Line 10: @@
 ==== Electron Current ====
-Before, we defined the electron current as the flow of electrons through the wire. We can make this more specific by defining electron current as the **number of electrons passing through a point per second**. Because the electron current is made up of negative charges, //the electron current will always flow opposite to the electric field//. (This is a more general rule that you may remember from before - electrons will always move opposite to the direction of the electric field.) We will use a lower-case "i" to represent the electron current:
+Before, we defined the electron current as the flow of electrons through the wire. We can make this more specific by defining electron current as the **number of electrons passing through a point per second**. Because the electron current is made up of negative charges, **the electron current will always flow opposite to the electric field**. (This is a more general rule that you may remember from before - electrons will always move opposite to the direction of the electric field.) We will use a lower-case "i" to represent the electron current:
 $$i=\frac{\# electrons}{second}$$
@@ Line 27: / Line 27: @@
 Conventional current is then defined as the amount of charge to pass a point per second (rather than the number of electrons). Because we already know the number of electrons passing a location, we can find the amount of charge per second simply by multiplying the electron current by the magnitude of the charge of a single electron. If the charge carriers aren't electrons (e.g., some kind of ion), then you will need to use the charge of the charge carrier. In the context of most circuits though, the electrons are almost always the charge that is moving. We will use an upper-case "$I$" to represent the conventional current and to distinguish it from the electron current.
 $$I=\frac{\# Coulombs}{second}=|q|i$$
-The conventional current is now positive (number of electrons times the magnitude of the charge). By "convention", the conventional current flows in the opposite direction of the electron current. In other words, the conventional current will flow in the //same// direction as the electric field. The units of conventional current are $\frac{Coulombs}{second}=\frac{C}{s}=A$, which we call an Ampere or an Amp for short. It is this conventional current that we measure with ammeters and multimeters in the laboratory.
+The conventional current is now positive (number of electrons times the magnitude of the charge). By "convention", the conventional current flows in the opposite direction of the electron current. In other words, **the conventional current will flow in the //same// direction as the electric field.** The units of conventional current are $\frac{Coulombs}{second}=\frac{C}{s}=A$, which we call an **Ampere or an Amp** for short. It is this conventional current that we measure with ammeters and multimeters in the laboratory.
 For historical reasons, much of what we work with in circuits is based off of conventional current rather than the electron current (much of what we know was established before we discovered it was the electrons that were free to move; you can thank [[https://en.wikipedia.org/wiki/Benjamin_Franklin#Electricity|Ben Franklin]] for that). However, remember that physically, the electrons are what move in a circuit.