electricity Flashcards
What is the circuit symbol for a switch?
switch - two circles with a line connecting them
What is the circuit symbol for a cell?
cell - a larger line and a smaller line parallel with a small gap between them
What is the circuit symbol for a battery?
battery - two cells with a dotted line joining them
What is the circuit symbol for a diode?
diode - circle with a line through it following the line of the wire, with a triangle with a line on it
What is the circuit symbol for a resistor?
resistor - rectangular box
What is the circuit symbol for a variable resistor?
variable resistor - resistor with arrow through it
What is the circuit symbol for a LED?
LED - diode with two small arrows coming off it
What is the circuit symbol for a lamp?
lamp - circle with X in it
What is the circuit symbol for a fuse?
fuse - rectangular box with line joining the wire going through it
What is the circuit symbol for a voltmeter?
voltmeter - circle with V in it (measures volts)
What is the circuit symbol for an ammeter?
ammeter - circle with A in it (measures amps)
What is the circuit symbol for a thermistor?
thermistor - resistor with line going through it that is flat just below the box
(used in thermostats)
What is the circuit symbol for a LDR?
LDR - resistor with circle around it and two arrows with the heads towards it
(used in outdoor lighting)
What is the function of a diode?
A diode makes the current in a circuit flow in only one direction.
What is the function of a resistor?
A resistor is fixed and restricts the current.
What is the function of a variable resistor?
A variable resistor means that the resistance can be changed and it restricts the current to a certain extent.
What is the function of a LED?
A LED is a diode that gives off light.
What is the function of a thermistor?
A thermistor changes the resistance based on temperature.
- as temperature increases, resistance decreases
What is the function of a LDR?
A LDR is a light dependent resistor.
- as light increases, resistance decreases
What is current? Give the unit.
Current is the flow of electric charge (electrons) around a circuit. It carries energy from the source and passes it to each component. It is measured in Amperes (A).
In what direction does current flow in a circuit?
Current flows in a circuit from the positive to the negative end of a cell.
What is potential difference? Give the unit.
Potential difference is the driving force that pushes a charge around a circuit. It is measured in volts (V). It is the energy per charge (Joules per Coulomb).
What is electrical charge? Give the unit.
Electrical charge is a property which experiences a force in an electric field. It is measured in Coulombs (C).
What is 1A, in terms of charge?
1A is 1C of charge flowing every second.
How do you calculate charge?
charge (C) = current (A) x time (s)
What is resistance? Give the unit.
Resistance is the potential difference required to drive a current through a component. It is measured in Ohms (Ω).