Electricity ⚡️

• Electricity is the movement of charged particles.
• The fuse value must be large enough to allow the appliance to operate normally.
• The power of an appliance is usually marked on the rating plate.
• If a TV uses 3 A of current, then a 13 A rather than 3 A fuse should be used.
• The current drawn by an appliance can be found using P=IV.
• Particles are either electrically neutral, positive, or negative.
• The most common charged particle we will be dealing with is the electron, which is negatively charged.
• If an electron is removed from an atom or molecule, the remaining piece becomes a positive charged particle called an ion.
• A material that loses electrons is positively charged, the item that removes the electrons will become negatively charged.
• Charge is given the symbol Q, from the Latin 'Quantitas ', which means amount.
• The charge can be thought of as the amount of electricity.
• Charge is measured in Coulombs, C.
• An electric field is the name given to a region where charges experience an electric force.
• Electric fields can be hazardous, for example, thunder and lightning.
• An Ohmmeter measures the resistance of a component and uses an internal power supply to measure the Voltage and Current it supplies, it also calculates resistance from those measurements, they have the following circuit symbol.
• Ammeters measure the current flowing through a component and are placed in series with the component, they have the following circuit symbol.
• When current passes through any material, the material opposes the charges moving through, this opposition to current is called resistance.
• The gradient of the line is the Resistance of the object, measured in Ohms, (Ω).
• Electrical symbols are used to make drawing circuits more standardised and easier to understand.
• The resistance depends on the type, thickness, and length of material and its temperature.
• Resistance is measured in Ohms (Ω).
• Thicker objects have lower resistance than thinner objects made of the same material.
• A LED has a voltage of 3.0 V across it and a current of 0.25 A passing through it, calculate the resistance of the LED.
• Metals are better conductors than nearly all non-metals, better conductors have lower resistance.
• Voltmeters measure the voltage, or potential difference, across a component and are placed in parallel with the component, they have the following circuit symbol.
• A Cell provides energy or voltage to a circuit.
• A TV remote control may only have one 1.5 V battery to supply enough energy to the LED transmitting the signal.
• As the temperature of conductors increases the resistance increases.
• The Resistance can be calculated using: R = V / I or R = V / I.
• A drone using four batteries to power its motors requires more energy than a TV remote control.
• A 1.5V battery supplies each Coulomb of charge going through it with 1.5 Joules of energy.
• To measure the resistance of any component a simple circuit can be made using a battery, voltmeter and ammeter as follows.
• The resistance of an object increases as its length increases.
• Ohm's law states the current in a conductor at constant temperature is directly proportional to the potential difference across it.
• Electrostatic discharges can easily damage microchips.
• Variable resistor limits current through other components, controls voltage across other components.
• Microphone converts sound energy into electrical energy.
• Photovoltaic cell converts light energy into electrical energy.
• Switch controls operation of a circuit.
• Loudspeaker converts electrical energy into sound energy.