In this chapter of AS/A-level Physics, you will learn about electricity.

Current is the rate of flow of charge --> depends on rate and time

Q= Charge in coulombs and t= Time in seconds

• Coulomb is a unit of charge --> amount of charge that passes 1 second if the current is 1 ampere (A)
• You can measure the current using an ammeter --> always attached in series

When it comes to AS/A-level Physics, potential Difference is the energy per unit charge
-    P.d or voltage is the work done per unit charge moved

-    Measured with a voltmeter --> always in parallel
-    Volt = The p.d across a component is 1 volt when you convert 1 joule of energy moving 1 coulomb of charge through the component 1V = 1JC-1

-    The amount of current for a particular p.d depends on the resistance of the components
-    Resistance measures how difficult it is to get a current to flow R inAS/A-level Physics

      -   Component has 1 Ω if a p.d of 1V makes a current of 1A flow through it
-    For Ohmic conductor, R is a constant --> most metals obey ohms law
-    If R is constant, then 𝐼 𝖺 𝑉

Semi conductors --> used in sensors
-    Not as good conductors as metals --> less charge available
-    IF energy is supplies to semi conductor then more charge carries can be released --> excellent sensors for detecting changes in their environment: Semi conductors can be Thermistors or  Diodes
-    As temp increases more electrons break free

Resistance in thermistors depend on heat/temperature in AS/A-level Physics
-    NTC thermistors --> negative temperature coefficient
-    Resistance decreases as temperature increases

Has same graph as filament for I/V
-    Warming thermistor gives more electrons energy to escape their atoms meaning more charge carriers available so resistance decreases

-   Only allow current to flow in one direction

You now can handle it.