Electricity Booklet Flashcards
What is electricity
A form of energy that is supplied by an electrical source
What must occur for atoms to form ions
The atom must lose or gain electrons
What do like charges do
Repel
What do unlike charges do
Attract
What is the relationship between charged and uncharged objects
Charged objects attract uncharted objects
What are the two types of circuit
+series
+parallel
What is a series circuit
A circuit in which all the components are connected one after the other (in a series).
What is a parallel circuit
A circuit which has more than one interconnected branches, in which each branch is independant.
What is electrical current
The rate of flow of charge in a circuit
What is current measured with and what is its equation
I= Q/T
it is measured with an ammeter
Measured in amperes
What is potential difference (voltage)
The amount of energy given to each coulomb of charge in a circuit
What is potential difference measured in and with and what is its equation
V= E/Q
it is measured with a voltmeter
Measured in volts
What is resistance
The opposition to the flow of charge in a circuit
What is the component of resistance
A resistor
What factors affect the resistance of a resistor
+ material of resistor
+ surrounding temperature
+ thickness of resistor
+ length of resistor
What is resistance measured in
Ohms
What is ohms law
V= IR or R= V/I
In a series circuit: does current add together or remain constant
Remain constant
In a series circuit: does voltage add together or remain constant
Add together
In a series circuit: does resistance add together or remain constant
Add together
In a parallel circuit: does current add together or remain constant
Add together
In a parallel circuit: does voltage add together or remain constant
Remain constant
In a parallel circuit: does resistance add together or remain constant
Different rule: 1/Rt= 1/R1 + 1/R2…
In a parallel circuit which branch receives the highest share of current
The branch with the lowest resistance
In a series circuit which component receives the highest share of voltage
The component with the highest share of voltage
What is power
The measure of how much energy is transferred in a circuit per second
What is power measured in and what is its equation
P= E/T
Watts
Why can the formula of power change
As they value depends on the original values that are given
What are the other equations of power
+ P= I(squared) x R (resistance and current given)
+ P= V(squared)/ R (resistance and voltage given)
+ P= IV (current and voltage given)
What are the two types of current in circuit
- alternating
- direct
What is a direct current
One which always flows in one direction - represented by a line on one side of the oscilloscope.
What is an alternating current
One which constantly flows in changing directions - represented by a line on both sides of the oscilloscope
What is the mains voltage of the UK
230 V
What is the mains frequency of the UK
50 Hz
What is a potential divider
Two components (usually resistors) connected in series.
How can you find the voltage of one of the resistors
V2= (r2/r1+r2) x Vs
In a potential divider, what happens to the voltage
It is split between the two components, proportional to the size of the resistance of each component.
What is the equation of the voltage being split in a potential divider
v1/v2 = r1/r2
What is an LDR
A light dependant resistor
What does an LDR do in light exposure increases
It’s resistance decreases
What is a thermistor
A temperature dependant resistor
What occurs as the temperature of a thermistor increases
The resistance decreases
What is the role of a protection resistor
A resistor which placed next to fragile components to prevent them from overheating or becoming damaged
What is the role of a fuse
To shut down the circuit if the current becomes too high or to prevent components from becoming damaged
What is a transistor
An electronic switch which consists of more than one component
What are the two types of transistor
+ NPN
+ MOSFET
What must the voltage be for an NPN transistor to close its switch
0.7 V
What must the voltage be for a MOSFET transistor to close its switch
2 V
What is the rating of a fuse
The current
