Ch19 Electric Circuits Flashcards
Define resistor:
A component in an electric circuit whose resistance decreases the current flowing
Define variable resistor:
A resistor whose resistance can be changed,
for example by turning a knob or moving a slider
Define light dependent resistor (LDR):
A device whose resistance decreases when light shines on it
Define relay:
A switch controlled by an electromagnet
Define NTC thermistor:
A resistor whose resistance decreases with increasing temperature
Define diode:
An electrical component that allows electric current to flow in one direction only
Define light-emitting diode (LED):
A type of diode that emits light when a current flows through it
Define potential divider:
A part of a circuit consisting of two resistors connected in series to obtain a smaller voltage than supplied
What is the equation for resistance for 2 resistors used as a potential divider?
R1/R2 = V1/V2
Define fuse:
A device that breaks the circuit if the current exceeds a certain value
A piece of metal wire that melts when too much current flows through it
Define trip switch:
Safety device that includes a switch that opens (trips) when a current exceeds a certain value
Define earthed:
When the case of an electrical appliance is connected to the earth wire of a three pin plug;
the Earth wire is electrically connected to the ground to prevent current passing through anyone touching a faulty appliance
Define double insulated:
When the electric circuit for an electrical appliance
is placed inside a case made from an electrical insulator
so that it is impossible for a live wire to touch the casing
