Circuits Flashcards
what is the ammeter?
The ammeter measures the current in amps flowing through the component. It must be placed in a series circuit but can be put anywhere n the series main circuit.
what is the voltmeter?
The voltmeter measures the potential difference in volts across the component. It must however be placed parallel around the component under test - NOT around resistor or battery
why does resistance increase with temperature?
As the electrical charge flows through a resistor, some of the electrical energy is transferred to heat energy and the resistor gets hot. This heat energy causes the ions in the conductor to vibrate more which makes it more difficult for the charge carrying electrons to get through the resistor - the current cant flow as easily and the resistance increases
what is a diode?
A diode is a special device made from semiconductor material such as silicon, it is used to regulate the potential difference in circuits. It only lets the current flow in one direction not the other
what are light emitting diodes?
A light emitting diode emits light when a current flows through it in a forward direction and they use a much smaller current than other forms of lighting (TV remote, digital clocks and traffic lights)
what is a light dependent resistor?
A light dependant resistor is dependant on the light intensity for the affect of it to be good ( Automatic night light and burglar detectors)
what is a thermistor?
A thermistor is a temperature dependant resistor, in hot conditions the resistance drops in cool conditions the resistance increases (car engine and thermostat)
