P2

Created by

alesha

Cards (11)

current is the flow of electrical change ions through a circuit, measured in amps
potential difference pushes the charge around the circuit and resistance slows the flow of current
$PD =$ $current *$ $resistance$
ohmic conductor - directly proportional, current and p.d rise at the same time
filament lamp - the resistance of filament lamp increases and temp filament increase
diode - current flows in one direction only
resistor - limits current flowing through it, can be variable or fixed
Series Circuit 
A circuit where devices are connected one after another, and the current flows through each device in sequence.
Advantage of Series Circuit 
Simple construction, uniform load, easy voltage measurement, high reliability.
In a series circuit potential difference is shared and current is the same and resistance add up
the bigger the component resistance the bigger the share of total P.D
the national grid distribute electricity which is a giant system of cables + transformers
power stations have to produce enough electricity for everyone
national grid uses a high potential difference + low Current
a step-up transformer increase voltage which decreases the current
alternating current is when current is constantly changing direction
direct current is current that flows in the same direction
main supply in the UK = 230V = AC
neutral wire = blue (completes the circuit)
earth wire = green + yellow (safety wire)
live wire = brown (alternate P.d)
advantages of parallel circuits include lower current flow per branch, higher efficiency as no energy lost due to heating effect, easier to repair if one part breaks down as other parts still working
in a parallel circuit, potential difference is the same across all component v1 = v2
current is shared between branches
adding a resistor reduces resistance
in a parallel circuit the current splits into two or more paths with equal potential differences but different resistances so current will be split between them