Lyceum A - Physics - Week 12 - Simple Electrical Circuits
- Feb 16, 2022
- 2 min read
A simple electrical circuit usually consists of four parts - a battery, a wire that goes from the positive pole of the battery to the negative pole of the battery, a light bulb in the middle (sometimes a buzzer is used instead) of that connecting wire so that the electrical current goes through the lightbulb and an off/on switch to interrupt or start the flow of electricity through the connecting wire.
From The Core Knowledge series:
The battery pushes negative electrons from the negative terminal which has too many electrons, through the wire to the lightbulb and then back to the wire, through the wire to the on/off switch, through the switch then back and finally through the wire into the positive terminal of the battery.
Inside the lightbulb is a filament wire and as electrons pass through the filament, the bulb lights up. When you hear a pop in a lightbulb and the lightbulb goes out, it means the filament broke and the flow of electrons can no longer make the connection.
The light switch works by opening the switch and making a gap in the circuit so that electrons can not flow through the wire. When you turn the light switch on, you are once again closing the gap so that the circuit is a complete circuit and electrons once again can travel through the filament.
The wire used in electrical circuits is usually made of copper metal. Copper is a very good conductor of electricity, which means that electrons flow through copper very easily. Silver is an even better conductor of electricity, but silver is too expensive to use.
Material like plastic, rubber, and glass are not good conductors of electricity as they permit almost no electrons to flow through them. For that reason they are good insulators and are used to cover electrical wires.
Batteries are great for creating the power to run small items like flashlights and portable radios. But bigger appliances, like refrigerators and stereo systems, usually require a more powerful source, like an electrical power plant.
Safety Rules for Electricity:
Always unplug any electrical device before working on it.
Turn off all electric circuit breakers before working on any electrical outlet.
Never stick anything into an electrical outlet, but especially anything metal. And that includes the toaster. You should always use wooden tongs to get bread out of a toaster, never your fingers or a fork, etc.
Never stick your finger into any electrical device, like a light socket or outlet.
Never touch a light switch or electrical appliance, even on the outside if it is plugged in, if your hands are wet or you are standing in any amount of water, even a tiny bit.
If you do any of these things, you risk making a complete electrical circuit that runs through your body and that is how people get electrocuted and die.
That is why a lot of handymen will do all kinds of carpentry and plumbing repairs, but leave electrical work to professionals.
Videos:
Electric Current: Crash Course Physics #28 - 8.22 min
Khan Academy - Coulomb’s Law - 11:50 min
Professor Dave Explains - Electric Charge and Electric Fields - 6:40 min
Comments