Electricity

• An ammeter is a component that measures the current flowing through a component, always placed in series to the component.
• A Voltmeter is a component that measures the voltage across a component, always placed in parallel to the component being measured.
• Electrical current is the flow of charge. (often electrons). Unit coulambs
• Voltage is the amount of energy in one coulomb of charge. Measured in volts (V).
• In a series circuit, different components need different amounts of voltage. (voltage is shared)
• In a parallel circuit current is the sum of the total current (current is shared) because

  • electrons go on different roads
  • flow of electrons
  • faster route
  • Slower route
• If electrons have more paths, they will be faster to get to the destination.
• When resistors are added in series, the total resistance increases.
• When resistors are added in parallel the total resistance decreases due to being more pathways.
• Movement of current is dependent on the long-line of the battery. Where ever the long line is facing, the current is moving that way.
• Resistance in parallel rule:

  $1/R^T =$$1/R^1 +$$1/R^2 +$$1/R^3 +$$...$
• Series resistance rule:

  $R^t =$$R^1 +$$R^2 +$$R^3$
• Each component has their own voltage requirements
• Each components have their own flow of current (depending on their position on a circuit)
• Each component has their own intrinsic resistance
• Always write the rules of a parallel and series circuit
• Remeber if the circuit is to complex, redraw the circuit
• V = Ep/ q (Electrical energy (J) / Charge (coulombs))
• Power is the amount of energy transformed per second. Measured in Watts (W).
• P = IR = I^2R = V^2/R
• Current is the measure of charge per second. I = q/t
• Disadvantage if a parallel circuit is that there is uneven current distribution which leads to overheating or overloading of indivdial component.
• An advantage of a series circuit is that they do not overheat easily.
• In ohmic devices the resistance will always stay at constant temp (follow the Ohms law)
• For non-ohmic devices the resistance changes over time which causes the temperature of the device to also increase.
• Series and Parallle circuits will consume different amounts of power.
• Series decreases overall POWER due to TOTAL resistance in series circuit to be larger.
• Parallel increases overall POWER due to TOTAL resistance being smaller in a parallel circuit.
• RELATE battery life to power usage, chemical potential energy, electricity potential energy.
• MORE resistance = MORE heat = MORE power (applied to that object)
• Non-ohmic devices: When there is an electrical current through a component with resistance the electrical energy being carried by the charge is converted into heat.
• Non ohmic devices: The increase in resistance the more heat is produced.
• If the total current changes, then the individual power of each component will ALSO change.

  • INDIVIDUAL VALUE of resistance remains the same
• Additional batteries in series MAINTAIN the SAME current BUT increase the VOLTAGE.
• Additional batteries in PARALLEL last longer, because the voltage remains the same, but the CURRENT increases.
• Electrons > Protons = Anions
• Electrons < Protons = Cations
• Conductors is a substance that allow electrons to flow freely through them.
• INsulators are substance that do not allow electrons flow easily through them.
• Charge separation occurs when the charge is transferred from one object to another.