electrical circuit Flashcards
what does a cell in a circuit ?
push electrons around the circuit
what is a battery made of ?
two or more cells joined together
what happens when a current passes through a lamp?
the bulb lights up
what is the function of a switch in a circuit ?
allows you to switch current on or off
what does a fixed resistor do ?
limits the amount of current flowing through
what is the purpose of a variable resistor ?
allows the current to be varied.
what does an ammeter measure ?
the current of a circuit
what does a voltmeter measures ?
the voltage of a circuit
what does a diode do ?
allows current to flow in one direction
what does an LED do ?
emits light when a current passes through it
what is a thermistor used for ?
works as a temperature sensor
what type of circuit has no branches?
series circuit
what types of circuit has branches ?
parallel circuit
what happens in a series circuit if one component breaks ?
the whole circuit stops working
why are series circuits useful ?
they give a warning if a component fails and use less wiring
in series circuit , what happens to the brightness if more lamps are added ?
the lamps become dimmer
in a parallel circuit , what happens if one component breaks ?
the other components keep working
what happens to lamp brightness in a parallel circuit when more lamps are added ?
the lamps stays bright
what is electric current ?
the flow of charge / electrons.
what is current measured in ?
amperes (Amps. A)
how must an ammeter be connected in a circuit ?
in series with the component
what is voltage (or potential difference ) ?
the energy needed make an electric current flow through a component
what unit is voltage measured in ?
volt (v)
what is used to measure voltage ?
a voltmeter
how must a voltmeter be connected in a circuit ?
in parallel with the component
what is resistance ?
the opposition to the flow of electric current through a conductor
what happens to resistance if the wire is longer ?
resistance increases
what happens to resistance if the wire is thicker ?
resistance decreases
why does a longer wire have more resistance ?
because electrons collide with more ions as they pass through.
what is the relationship between wire length and resistance ?
they are proportional.
what is a series circuit ?
a circuit with no branches , components are in one path
why are parallel circuits useful
components operate independently
what is needed to make current flow
a voltage or potential difference
when can current not flow
when the circuit is incomplete or has no power source
