p2- electric circuits Flashcards
what is a switch?
A switch used to turn a circuit on (closed) and off (open).
what is a lamp?
An electrical current heats the filament in a bulb so that it gives out light
what is a fixed resistor?
A resistor restricts or limits the flow of electrical current. A fixed resistor has a resistance that does not change
what is a variable resistor?
Moving the position of the slider on this resistor, changes the resistance. A variable resistor is used in some dimmer switches and volume controls.
what is a thermistor?
The resistance of a thermistor depends on its temperature. At low temperatures, the thermistor has a high resistance. As the temperature increases, the resistance decreases. A thermistor can be used in thermostats or heat activated fire alarms.
what is an ldr?
The resistance of a LDR depends on light intensity. At low light levels, the LDR has a high resistance. As the light intensity increases, the resistance decreases. A LDR can be used as a sensor in cameras or automatic lights that come on when it gets dark
what is a semiconducter dioce
A semiconductor diode allows current to flow in one direction only. Current will not flow in the other direction. Diodes are used to convert an alternating current into a direct current
what is charge?
Electrons are negatively charged particles and they transfer energy through wires as electricity.
how do you calculate charge?
charge = current × time
how do you calculate potential difference
potential difference = current × resistance
what is current in a series?
A series circuit is one loop; all electrons in that loop form one current. An ammeter will measure the same current wherever it is placed in the circuit:
how do you calculate power?
power = current × potential difference
