voltage & amps Flashcards
The size of the electric current is the rate of flow of _________.
electrical charge.
Current is equal to _____ divided by time.
charge
units for charge
coulombs
a current of of 1 ampere =
1 coulomb of charge flowing per second
An electrical insulator has_______
no free electrons. No charges are free to move and carry a current.
Which charges are free to move in metals?
electrons
all ______ are electrical conductors
metals
The energy is transferred to the electrical components in a circuit when ____________________.
the charge carriers pass through them.
what is potential difference
it is the energy difference per unit charge between two points in a circuit
potential difference =
current x resistance
If the resistance is increased, the current will _______
decrease
If the potential difference is increased the current will _______.
increase.
An electric current will increase when the number of ohms ______.
decrease
On a current-voltage graph for a resistor, the slope of the graph is equal to _______.
1/resistance
Resistance is a measure of how difficult it is for ______ to flow through a component.
current
what is a rectifier ?
A component that turns an alternating current (repeatedly changes direction) into a direct current (one direction).
_______ act as rectifiers as they block the alternating current when it changes direction.
Diodes
of a rectifier, the output current is
direct current (DC)
of a rectifier, the input current is
alternating current (AC)
What is a thermistor ?
A component where resistance changes with its temperature.
What are light dependent resistor (LDR)s .
A component whose resistance changes with light intensity.
The current through an ohmic conductor (at a constant temperature) is _______.
directly proportional to the potential difference across the resistor.
In an Ohmic conductor, the resistance…
remains constant
R=
P÷I 2
A resistor …… the flow of current…….
opposes ………. but does not reduce it.
Vtotal=
V1+V2+V3
Consider a circuit with two resistors of equal value connected in series. If another resistor of the same value is connected in parallel with ONE of these resistors, what will be the effect on the total resistance of the circuit?
the resistance decrease
Two ohmic conductors are connected in series, with the second conductor having a larger drop in potential difference across it. What can be determined about the values of the resistances of the conductors?
the second conductor must have a higher resistance
What two things will happen to a bulb that is connected in series with a thermistor, as the temperature on the thermistor changes?
at higher temperatures the bulb glows brighter and at high temperatures there is a higher potential difference across the bulb
