Chapter 12 Flashcards
What does a cell do?
It supplies energy to the charge (electrons) so they can flow around the circuit.
What equation links voltage energy and charge?
Voltage = Energy/ Charge
What is the current?
The rate of flow of Charge
What is the equation linking Current, time and Charge?
Charge = Current x time
What is the voltage (potential difference)?
The work done per unit charge
What is Emf (Electromotive force)?
The electrical energy produced per unit charge passing through a source
Emf equation
E = V + Ir
Power equation involving current and resistance
P = I^2 x R
What is different about diodes?
They only allow current to flow in one direction
What happens to the resistance of a wire as temperature changes, and why?
Resistance increases with temperature as the ions vibrate more, making current transfer harder (so it has a positive temperature coefficient)
How conductive is and intrinsic (pure) semiconductor?
Better at conducting than insulating but not as good as a conductor.
What is an example of something made from an intrinsic semiconductor?
A thermistor
What is an example of a component with a negative temperature coefficient and what does this mean?
An example is a thermistor, and this means that resistance decreases when temperature increases
