electricity Flashcards
What is the current
flow of charged particles through an electrical conductor
how is the current represented
amperes(A)
how is the current measured?
using an ammeter
what is the potential difference
the work done to move charge between two points
how is the p.d. represented
V
What is the equation to represent the relationship between energy,charge, p.d
E=QxV
what is to energise, charge VO!
energy= charge x p.d
how is potential difference measured
voltmeter
what is the resistance
opposition of the flow of current through a conductor
how is resistance represented
resist virtual intelligence
R=V/I
what is a voltage current graph
displays the relationship between V and A
what is an ohmic conductor
a fixed resistor that maintains constant resistance
what is a non-ohmic conductor
not constant and produce a sigmoidal curve
explain this graph
as more current flows through a filament lamp
it heats up due to the increase electron collisions
this heat leads to an increased resistance as the particles vibrate with more energy
making it harder for free electrons to flow through
decrease in current
what are thermistors
components whose resistance is dependent on temperature
explain this graph
as the temperature increases, resistance decreases
what is a light dependent resistor(LDR)
components whose resistance is dependent on the light intensity
explain this graph
resistance of ldr decreases as light intensity decreases
what is an ideal diode
components that allow current to flow in one direction
what are the practical characteristics of ideal diodes
require a forward junction potential before current flows through it
have a break down voltage in the reserve direction causing negative current
what is the ideal characteristics graph of a diode
what is the practical characteristics of a diode
what’s a series circuit
current is the same in every component
what is the p.d in series
the sum of all the p.d components
what is the resistance in series
sum of all the components
what is a parallel circuit
where the components have branches
what is the p.d in parallel
the same to the overall p.d
what is the current in parallel
sum of all the branches to overall
what is reciprocal law
what is power
the rate of work done
energise, personal trainer
E= p x t
how can transfer of electrical power be measured
p = v x I
relationship between power, current and resistance
P= i2 xR
what is a transformer
devices that have the ability to alter V and A
what is a step-up transformer
increase voltage and decreases current
what is a step-up transformer useful for
transfer of electricity from power stations to national grid to reduce energy loss
what is a step down transformer
to decrease voltage and increase current
what is a step down transformer useful for
to use in homes to reduce risk of electric shocks
what does a transformer consist of
primary coil wrapped around a core
what happens in this transformer
current flows through the primary coil
creates a magnetic current which induces secondary coil
A and V can be altered by varying the ratio of turns in the coils
equations for transformers
power = primary voltage x primary current
power = secondary voltage x secondary current
what is the generator effect
generation of a current by the movement of an electrical conductor relative to a magnetic field
what does a generator consist of
wire rotating in a magnetic field
what happens as the wire rotates through a magnetic field
each side of the coil moves through the field in two different direction with each 360 rotation, producing ac
what is a waveform
current changing direction at a certain regular frequency
what is the frequency and voltage in the uk
50 Hz and 230 V
what is an electrostatic conductor
material that is able to disperse electrons easily
what is an electrostatic insulator
doesn’t disperse electrons easily
what happens when insulators are rubbed together
flow of charge from one to other
loss of electrons is positive
gain is negative
what happens to objects with the same charge
they repel each other
if opposite charge they attract
