From bfe47536fca5699860653825dbe3714d142470d0 Mon Sep 17 00:00:00 2001 From: tactonbishop Date: Thu, 25 Aug 2022 08:30:05 +0100 Subject: [PATCH] Last Sync: 2022-08-25 08:30:05 --- Electronics/Physics_of_electricity/Current.md | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/Electronics/Physics_of_electricity/Current.md b/Electronics/Physics_of_electricity/Current.md index fbf1b7a..e240d8b 100644 --- a/Electronics/Physics_of_electricity/Current.md +++ b/Electronics/Physics_of_electricity/Current.md @@ -8,14 +8,15 @@ tags: [physics, electricity] > Electrical current is the movement of electrons from negatively charged atoms to negatively charged atoms when an appropriate external force is applied. -So current is the flow of electrons. Charge is the quantity that flows. +So current is the flow of electrons. Charge is the quantity that flows. > The amount of current is the sum of the charges of the moving electrons past a given point. ## Why current exists + Current exists because of the [first law of electrostatics](/Electronics/Physics_of_electricity/Coulombs_Law.md). -When there is an excess of electrons at one terminal (i.e. negatively charged atoms) and a deficiency of electrons at the other terminal (i.e. positively charged atoms), a _difference of potential_ exists between the two terminals. +When there is an excess of electrons at one terminal (i.e. negatively charged atoms) and a deficiency of electrons at the other terminal (i.e. positively charged atoms), a \*\*difference of potential\_ exists between the two terminals. When the terminals are connected to each other via a conductor (e.g. copper wire) electrons will flow along the conductor. This is provided that there is a source to supply electrons at one end and remove them at the other. We call this force the **voltage source**. @@ -28,9 +29,9 @@ _The diagram below illustrates the flow of current where the circles are electro ## Formal expression We measure **charge** in Coulombs ($C$). A Coulomb is an aggregate of the charge of thousands of electrons because their individual charge is so small. -One Coulomb is equal to the charge of $6.24 \cdot 10 ^{18}$ electrons. +One Coulomb is equal to the charge of $6.24 \cdot 10 ^{18}$ electrons. -We measure **current** in amps. When one coulomb of charge moves past a point in one second it is called an **ampere** (amp) represented as $A$. +We measure **current** in amps. When one coulomb of charge moves past a point in one second it is called an **ampere** (amp) represented as $A$. This relationship is captured in the following equation: @@ -38,14 +39,15 @@ $$ I = \frac{Q}{t} $$ -* $I$ = current measured in amps -* $Q$ = quantity of electrical charge measured in coulombs -* $t$ = time +- $I$ = current measured in amps +- $Q$ = quantity of electrical charge measured in coulombs +- $t$ = time ### Application + _Calculate the current in amps if 9 coulombs of charge flow past a point in an electric circuit in 3 seconds._ $$ I = \frac{9}{3} \\ I = 3 A -$$ \ No newline at end of file +$$