Electric Circuits Flashcards
Electric circuits
convert electrical energy into other forms of energy we need
Primary cell
Chemical reactions use up some of the materials in the cells as electrons flow
Cells become discharged and can’t become recharged
Primary wet cell
2 pieces of metal are placed in a liquid
The metal is called the electrode (ex. Copper, zinc) and the liquid is called the electrolyte (usually and acid; composed of ions)
The electric charges remain static on the electrodes until connected to a closed electric circuit which discharges the cell
Primary dry cell
Function is similar to a wet cell but the electrolyte is a moist paste
When the negative electrode has been used up by chemical reaction the electrons stop flowing and the cell is discharged
Ex. Batteries, flashlights, watches
Secondary cells
Can be discharged and recharged
Ex. Cell phone, laptop batteries
Some wet cells are also secondary cells (ex car battery)
Fuel Cells
Generates electricity from a chemical reaction with fuel
Ex. Hydrocarbon (gas)
Most of the energy is lost as heat
As the electricity is produced, more fuel is added (not used up)
Used in a wide range of applications including transportation
Potential Difference
The difference in electric potential energy between 2 points (negative and positive end of a battery) is called potential difference (voltage)
The higher potential difference, the greater the potential of each electron
Potential Enterance
Each electron has electrical potential energy
Potential energy is the energy stored in an object
A battery has chemical potential energy
Current
Is a continuous flow of electrons in a circuit
Is a measure of the amount of electric charge that passes through a circuit
Ex. Water flowing in a stream
direct current (DC)
Flows in only one direction
Ex. Batteries in a circuit
alternating current (AC)
Flows back and forth
Ex. Cords plugged into wall sockets
Current comes from generators
Current electricity
flow of electrons in a circuit through a conductor
Static electricity
electric charge that builds up on the surface of an object
Static electricity discharges when it is given a path, but it does not continue to flow
Resistance
The degree to which a substance opposes the flow of electric current through it
Conductors allow electrons to flow freely and have low resistance values
Insulators resist electron flow greatly and have high resistance values
Measure in ohms Ω using an ohmmeter
wire-wound resistor
A wire-wound resistor has a wire made of heat-resistant metal wrapped around an insulating core
The longer and thinner the wire, the higher the resistance
