It's been a long time since doors had only brass knockers or manual crank doorbells. The basic electric door buzzer and doorbell that first replaced these devices are still in use in many homes, but technology has moved on. You can now choose from various door chimes, electronic programmable door chimes and even wireless models. Take this quiz to see if it rings your chimes.
What is an electromagnet?
An electromagnet is a permanent magnet created by subjecting a piece of iron to high current.
An electromagnet is a large spinning disc used to generate alternating current.
An electromagnet is a piece of insulated wire wrapped in a coil that is magnetized when current is applied.
What property do both permanent magnets and electromagnets have in common?
Both have polar orientations.
Both repel metal objects.
What will happen when two de-energized electromagnets are placed close to each other?
They will repel.
They will attract.
What is an electrical transformer?
A transformer is an electrical device that changes alternating current to direct current.
A transformer is an electrical device used to reduce voltages in electrical circuits.
A transformer is an electrical device used only in fluorescent light fixtures.
How does a door buzzer work?
An electromagnet operates a self-interrupting circuit to produce a buzz.
An electromagnet causes a magnetic ball bearing to jump around inside a metal cylinder creating a buzz.
Two electromagnets make a bimetallic strip jump back and forth between them.
How does a simple doorbell work?
When you push the button, a small motor inside the bell spins an arm with two clappers that strike the bell.
An iron bar inside an electromagnet is pushed out by the magnet and retuned by a spring striking a bell as it moves.
It works exactly like a door buzzer, except the contact arm is attached to a clapper that strikes a bell as it vibrates.
What is the name of the special electromagnet used inside a chime doorbell?
How does the piston in a solenoid move in and out of the electromagnet coil?
Magnetism from the coil repels the piston and a spring returns the piston when the coil is de-energized.
When the coil repels the piston, voltage reverses and pulls the piston back the other way.
There are two coils wound in opposite directions causing a constant push pull motion.
What happens if you hold down the door chime button when you are standing at the door?
The door chime will keep dinging without any dong until you release the button.
The door chime will simply make a very annoying rattling noise and can damage the chime mechanism.
The door chime will only ding once and not dong until you release the button.