Electricity Flashcards
P. 109 - 116
what did you learn about in Grade 6 about a simple electrical circuit
- cell = source of electrical energy in the circuit. uses chemical energy to make electrical energy, in this way i transfers energy from its chemical to the circuit
- the insulated connected wires carry the electrical energy through the circuit
- lamp uses the electrical energy in the circuit to make light and heat energy. lamp transfers this energy from circuit to environment.
what does a electrical circuit consist of
electrical energy source - battery
electric components - switch, bulb / buzzer etc.
insulated wires - connect everything together + provide pathway for the electrical energy to flow through
what are insulated wires also known as in a circuit and what is their purpose
known as conductors
purpose = carry electrical energy
describe all the components of an electrical circuit
cells and cell holders:
all electric circuits require source of electrical energy. in most circuits the cell is the source.
cells are marked with number called the voltage which is an indication of cells ability to “push” energy through circuit. higher the voltage, greater the “push” and more electrical energy flows through circuit.
many different size cells. in tech classes, usually use AA cells. but sometimes you might use size D cells, which are bigger. notice P 111 cell holder has 1 black + red wire.
- red wire = connects positive terminal, marked with a +
- black wire = connects negative terminal, marked with a -
Connecting wires and connections
safety reasons, you should use insulated connecting wires in circuits. insulated wires cover with plastic coating to prevent bare wires touching. if uninsulated wire used, parts of circuit can accidentally touch causing a short circuit. in short circuit, electrical energy takes shorter / different path than intended. can result in circuit not working properly, cells energy wasted.
wires connected using crocodile clips, connector strips, nails that have been hammered into wood, or by twisting bare wires together and wrapping them with insulation tape. in tech class, you’ll use crocodile connectors to make most connections.
Lamps and lamp holders
twist-in lamps we use in tech classes are MES (Medium Edison Screw) lamps. we usually use 2.5 V / 3.5 V / 6.5 V MES lamps. the voltage written on lamp (the rated voltage) must not be less than the voltage across lamp in the circuit, otherwise bulb will burn out.
there are two common types of MES lamp holder - brass and plastic. brass lamp holders are cheaper and easier to connect, but plastic lamp holders have broad bases that are easier to screw onto a piece of board.
Switches
many types of switches. we usually use:
- press or push switches, that stay on as long as you press them.
- toggle or single pole single throw (SPST) switches that stay on until switched off.
also use homemade switches, paper clip and matchbox switch.
what must you do if your circuit doesn’t work (troubleshooting)
check the following:
- are the connections loose?
- is the circuit broken?
- is the cell flat/dead?
- is the bulb broken/blown?
- does the switch work?
What are short circuits and how do you avoid them (safety)
it is when bare connectors accidentally touch. the bare ends of the wires of the cell holder often touch accidentally. a short circuit can be avoided by not inserting the cell into the cell holder until you are ready to switch the circuit on.
describe the relationship between an AA and a D cell and what is an AA cell known as
AA cell known as a penlight cell.
an AA cell and a D cell are both 1,5 V, but the D cell lasts longer.
what are components
the electrical parts in a circuit
what is an electromagnet and a solenoid
an electromagnet is a temporary magnet created by an electric current flowing through an insulated wire, it can be turned on and off.
a solenoid is a coil of insulated wire in the form of a cylinder that forms a magnet when an electric current flows through it
where are large electromagnets commonly found
metal recycling plants, it separates the magnet metals from the non-magnetic metals
what does a simple electromagnet consist of a
length of insulated wire that is wound around a piece of iron, known as a solenoid. the magnetic field is created when the electric current flows trough the coil.
