Electrecity Flashcards
Cell
This has a store of chemical energy. The larger line shows the positive terminal and the short line shows the negative terminal
Battery
2 or more cells joined together
Switch
This sitches on and off, determining if the current is on or off
Lamp
This lights and heats up when the current flows through it
Variable resistor
This can vary the size of the current
Fixed resistor
The value of the resistor affects the size of the current
Voltmeter
Measures the potential difference
Ammeter
Measures the current
Motor
This rotates when the current flows
Heater
is designed to transfer electric current into heat energy in the surrounding
Diode
Allows current through in one direction only
A light emittent diode( LED)
Emits light when a current passes through it
A fuse
Designed to melt and therefore break the circuit if the current through it is a greater amount
Triangle for charge flow( Q), current( I), time taken( t)
Q
I T
What is charge measured in
Coulumbs( C)
What is current measured in?
Amps(A)
What is time taken measured in?
seconds
When 2 insulators are rubbed together…
they become electrically charged
What force allows electrons to move from one insulator to another
friction
Electrons move when 2 insulators are rubbed together
because of friction and they are light and outside of the nucleus
positive and positive
repel
negative and negative
repel
positive and negative or negative to positive
attract
conductors and insulators are charged by
induction
if charge is 240 and time is 2 min what will the current be
2A
electrical resistance
is a measure of a components flow of current
If the resistance of a variable resistance increases the current will…
decrease
If the resistance of a variable resistance decreases the current will…
increase
When was Ohm s law made
1927
Ohm’s law is the fundamentals of…
current, voltage resistance
Ohm’s law measures…
conductors
the equation for voltage, current, and resistance
V=IR
Voltage= current*recistance
Ohm’s law
relationship between voltage current and recistance
What is the full form of DC
direct current
Full for of AC
alternative current
DC
only flows in one direction
AC
Changes directions periodically
Reversing the potential difference across resistor reverses
the current through it
Recistance in a Filament lamp
The line curves away from the y-axis. So the current is not directly proportional to the potential difference. It is a non- ohmic conductor
the resistance of a metal increases as the temperature increases. Atoms vibrate more as temp. increases so they resist more from electrons passing
Reversing the potential difference reverses the current and makes no difference to the shape of the curve. The resistance is the same for the same current, regardless of direction
Resistance in a diode
Current flows in one direction only, called the forward direction
Non- Ohmic conductor as the line curves toward the y- axis. Resistance is not directly proportional
Forward resistance low; reverse resistance high
also depends on which way it is connected
Resistance in a Thermistor
Resistance decreases if the temperature increases
temperature-dependent resistor
Resistance in LDR
temperature decreases if the light intensity increases
Full form of LDR
Light-dependent resistor
In a series circuit more resistors =
more resistance
R( on the leg T) = R( on the leg1)=R( on the leg of 2)…
In a series circuit current=
same throughout circuit
I( on the leg T)= I( on the leg 1)= I( on the leg 2)
In a series circuit, Voltage:
Voltage adds up
V( on the leg T)= V(on the leg 1)+V(on the leg 2)…
R( on the leg T)=
R( on the leg eq)
I( on the leg T)=
I( on the leg eq)
V( on the leg T)=
V( on the leg eq)
In a parallel circuit, total current=
the sum of the currents in separate branches
I( on the leg T)= I( on the leg 1)+ ( on the leg 2)…
In a parallel circuit, potential difference across all branches
must have the same magnitude
V( on the leg T)= V( on the leg 1)= V( on the leg 2)= ( on the leg 3)…
The reciprocal of the equivalent resistance is equal to …
the sum of the reciprocal of the separate resistance parallel
I/ R( on the leg T)=I/ R( on the leg 1)+ I/R( on the leg 2)
