Current Resistance and Resistivity

• Electric circuit - is a path of an electric current.
• Closed circuit - allows the current to flow from the source of the current to the load where the current is needed.
• Open circuits - have “gaps” where current cannot flow.
• Short circuit - is a closed circuit in which direct connection is made.
• Current - is any motion of charge from one region to another. The vast majority of technological applications of charges in motion involve currents of this kind.
• The SI unit of current is the ampere (A)
• Electron Flow  - Electrons flow out of the negative terminal, through the circuit and into the positive terminal of the source.
• Conventional Current - assumes that current flows out of the positive terminal through the circuit and into the negative terminal of the source.
• Electromotive force - energy per unit electric charge that is imparted by an energy source, such as an electric generator or a battery.
• Direct Current - electric current with the same direction
• Alternating Current - electric current with its direction and values keep changing. 
• Resistance - The limitation of current flow.
• Ohm's law - states that the voltage or potential difference between two points is directly proportional to the current or electricity passing through the resistance, and directly proportional to the resistance of the circuit.
• I-V Curve Ohmic Device - Any device that demonstrates Ohm’s Law
• I-V Curve Non-Ohmic Device - Any device that doesn’t demonstrate Ohm’s Law
• Resistivity - describe how strongly a material resist the flow of electric current.
• Resistivity - is a measure of the resistance of a given size of a specific material to electrical conduction.
• The unit of resistivity is ohm-metre (Ω·m)
• The unit of resistance is the ohm (Ω)
• Current density - The amount of electric current traveling per unit cross-section area. Expressed in A/m^2
• Conductance - The inverse of resistance
• Conductivity - inverse of resistivity
• Shuttered sockets - Sockets fitted with internal protective shutters, making it difficult for children to poke things inside it
• Fuse - Protects the circuit from excessive current by melting if the current is high enough, opening the circuit, and stopping the current flow
• Circuit breaker - Protects the circuit from current overload; functions similarly to fuses, but does not get destroyed, making this a long-term safety device
• Ground fault circuit interrupter - Designed to detect a tiny mismatch in currents to prevent electrocution; mandatory in bathrooms, kitchens, or anywhere else in the house where water may come in contact with an electric circuit.
• Three-pronged plug - A plug with a round prong that serves as the ground outlet for the device, which connects to the ground wire of the building
• Burns - Low-to-high powered voltages that can cause minor to serious injuries
• Muscle cramps - An uncontrollable muscular twitching due to electrical overstimulation.
• Ventricular Fibrillation Cramps - The same as muscle cramps, but affects the heart.