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What does a basic battery consist of?
Two dissimilar metals and an electrolyte.
What determines the voltage of a battery?
The type of metals and the electrolyte.
How do fuel cells produce EMF?
By combustion / chemical oxidations (oxygen ionically bonding with other elements). Basically a battery with a continuous supply of chemicals.
What is an example of a fuel cell?
The Hydrogen-Oxygen cell.
What does a Hydrogen-Oxygen cell contain?
Contains hollow, porous, carbon electrodes immersed in a potassium hydroxide solution.
What are the gasses supplied to a Hydrogen-Oxygen cell?
Hydrogen gas is supplied to one electrode and oxygen gas is supplied to the other.
What acts as the catalyst in the electrodes of a Hydrogen-Oxygen cell?
The carbon electrodes contain metal or metal oxide that acts as a catalyst.
What is a catalyst?
A substance that increases the rate of a chemical reaction without being consumed in the process.
What are the products of the Hydrogen-Oxygen cell?
Electricity (Voltage & current), Water, Heat (small amount)
What is a thermocouple?
A device that converts temperature differences directly into electrical voltage, using the Seebeck effect.
What is the Seebeck effect?
EMF generated across two different conductors or semiconductors when there is a temperature difference between them.
What are some applications of thermocouples?
Temperature sensors for relays & cutoff valves, Outside Air Temperature (OAT) sensors
What is Piezoelectricity?
The generation of electrical charge in certain materials when they are mechanically stressed or deformed.
What are some typical materials used in piezoelectric devices?
Quartz (SiO2), Barium Titanate
What are some applications of Piezoelectricity?
Igniters, Engine knock sensors, pressure sensors, diesel fuel injectors, transducers
What is the photoelectric effect?
The phenomenon where electrons are emitted from a material when it absorbs light or electromagnetic radiation.
Which pure material do solar cells require?
Ultra-pure silicon
What is the maximum output of a 1cm x 2cm solar cell?
50 mA at 0.5V
What are the different material types for solar panels?
Thin film, mono-crystalline, polycrystalline
What is Electromagnetic Induction / Generator Action?
A changing magnetic field induces an electromotive force (EMF) in a conductor.
What is Faraday’s Law of Induction?
The induced EMF in a circuit is proportional to the rate of change of the magnetic flux through the circuit.
What are the factors affecting induced voltage from magnetism?
Strength of magnetic field, speed of movement, angle between conductor and magnetic field lines, length of conductor
What is a generator?
A device that uses electromagnetic induction to produce an EMF.
What is tribocharging?
Generating electric charge through friction between two different materials, leading to an imbalance of electrons. (Eg. Walking on carpet, exiting a car, removing plastic covering)
What happens to the Van de Graaff generator when a load is attached?
The current remains the same and the voltage varies.
