Electricity Flashcards
(30 cards)
Circuit symbols
Pg54
Electric current is
The flow of electric charge
The greater the rate of the flow,the higher the current
Current is measured in
Amperes
Amps
Measures using an ammeter
Electric charge is measured in
Colombes
Charge flow=
Current x time
The resistance of a component is
The measure of how it resists the flow of charge
The higher the resistance
The more difficult it is for the charge to flow
The lower the current
Resistance is measured in
Ohms
Voltage is also know as
Potential difference
Voltage tells us
The difference in electrical potential from one point to another
Potential difference can be thought of as
Electrical push
The bigger the potential difference:
The greater the flow of charge through the component
The bigger the current
Voltage is measured in
Volts
Using a voltmeter
Voltage=
Current x resistance
Required practical
Pg 55
straight line through origin on graph
Voltage and current and directly proportional
Resistance is constant
Steep gradient
Low resistance
Large current for a small potential difference
Shallow gradient
High resistance
Large potential difference is needed to produce a small current
Non linear graphs
Resistor is not constant
Resistors
Ohmic conductor= current is directly proportional to potential difference
Resistance remains constant
Filament lamp
As current increases the temperature increases
This causes resistance to increase current increases
Diodes
Current will only flow in one direction
Very high resistance in other direction
Thermistors
Resistance decreases as temperature increases
Useful where temp control or response is needed
Light dependant resistors
Resistance decreases as light intensity increases
Useful where automatic light control or detection is needed
