Electricity - Daniel Segulin Flashcards
(21 cards)
What is current? What is it measured in?
Current is the flow and speed of electricity through a circuit. It is measured in amperes (A), or coulombs of charge per second.
What is voltage? What is it measured in?
Voltage is the ‘push’ given to electrons in a circuit. It is measured in volts (V), or joules of energy per coulomb of charge.
What is resistance? What is it measured in?
Resistance is the force opposing the flow of electrons in a circuit. It is measured in ohms (Ω).
What is DC current?
DC current, or direct current, is a constant flow of electricity in a circuit always travelling in one direction.
What is AC current?
AC current, or alternating current, is a varying flow of electricity in a circuit that changes in its direction of flow.
What is an ohmic device/conductor?
An ohmic device/conductor is something that follows Ohm’s Law, that is, its resistance remains constant regardless of voltage or current changes.
What is a non-ohmic device/conductor?
A non-ohmic device/conductor is something that doesn’t follow Ohm’s Law, that is, it’s resistance varies as the voltage or current is changed.
What is Ohm’s Law?
Ohm’s Law states that the voltage in a circuit or over a device is equal to the current flowing through it multiplied by its resistance. It is written as V=IR. The equation can also be transposed to find current and resistance.
What is a series circuit?
A series circuit is one in which electric current only has one path to flow through.
What is a parallel circuit?
A parallel circuit is one in which electric current has more than one path to flow through.
How does current behave in series?
In a series circuit, current remains the same throughout.
How does current behave in parallel?
In a parallel circuit, total current is divided between each branch and comes together again at junction points.
How does voltage behave in series?
In series circuits, voltage is different across all components and the total voltage drop in the circuit is equal to the power supplied to it.
How does voltage behave in parallel?
In parallel circuits, voltage remains the same throughout.
What are Kirchhoff’s Laws?
Kirchhoff’s Laws state that at junctions, the current entering is equal to the current exiting and that the voltage across an entire circuit is zero, or that the total voltage drop in a circuit added to the voltage supplied to the circuit is zero.
How is total resistance found in series circuits?
The total resistance of series circuits can be found by adding all resistance together.
How is total resistance found in parallel circuits?
The total resistance of parallel circuits can be found by adding the inverse of all resistance together and finding the inverse of that sum.
How are power, voltage and current related?
Power in watts is equal to voltage in volts multiplied by current in amperes, or P=VI
How are energy, charge and voltage related?
Energy in joules is equal to charge in coulombs multiplied by voltage in volts, or U=qV
How are charge, current and time related?
Charge in coulombs is equal to current in amperes multiplied by time in seconds, or Q=It.
What are the characteristics of Australian household electricity?
Australian household electricity is AC, having a frequency of 50Hz (50 changes in direction per minute) and therefore a period of 0.02s. The voltage (RMS) of this electricity is 240V, which is the equivalent of the DC voltage to produce the same power.
