Current and voltage

• Current = charge / time
• voltage = energy / charge
• electric current is the rate of flow of charged particles
• conventional current is the rate of flow of charged particles from the positive to negative terminal of a cell
• Electron flow is the flow of electrons from negative to positive
• voltage is the energy stored in each unit of charge
• an ammeter is used to measure current
• an ammeter must always be place in series
• a voltmeter is used to measure voltage
• it must be placed in parallel
• a series circuit has only one path for the current to flow around
• in a series circuit current is the same everywhere in the circuit
• in a series circuit the sum of the voltages across the individual components is equal to the power supply
• in a series circuit if one component breaks the others will not work
• in a series circuit you cannot turn components on and off individually
• If you add another bulb to a series circuit all the bulbs will get dimmer as voltage must be the same on all bulbs
• in a parallel circuit there are many paths for the current to flow around
• in a parallel circuit the sum of the currents in each branch is the same as the current in the pain part of the circuit
• in a parallel circuit the voltage in each branch is the same
• in a parallel circuit if one component breaks the rest will continue to work
• in a parallel circuit you can turn components on and off individually
• if you add another bulb to a parallel circuit the brightness of other bulbs will stay the same since the voltage across each bulb stays the same
• the brightness of each bulb in a parallel circuit depends on the power, calculated by multiplying the voltage and current
• Units of charge are columbs (C)
• units of current are Amps (A)
• units of time are seconds (S)
• units of voltage (potential difference) are Volts (V)
• units of energy are joules (J)
• E = QV
• In a series circuit voltage is shared amongst components: V(total) = V1 + V2 +V3
• in a series circuit current is constant in all parts
• in parallel circuits all components get the full voltage: V(total) = V1 = V2 = V3
• in a parallel circuit current is split between branches based on resistance