Bells and Buzzers Can Tell a Lot
Electric bells and buzzers use the same basic principle as the telegraph system, invented by Samuel Morse in 1840. Although not as important today as it was before radio, telephone, and teletype became common, the telegraph is still in use.
Bells and buzzers, however, are very common and have many uses. They are most often seen in the form of doorbells, and rare is the new home that does not have one or more. Service stations have bell systems to let the operator know that a car is waiting at the gas pumps. A clock signal reminds the homemaker when the cooking time is completed. Children are called to and released from school classes by means of bells and buzzers.
Also, various alarms employing bells and buzzers warn us when it's time to get up, or even that the place is on fire, or that a burglar is trying to break in!
Let's find out how bells and buzzers work, what different kinds there are, the different ways you can control them, and how you can put them to work for you.
You'll find that buzzers and bells can help you with your 4-H projects, and with the proper controls, can be your eyes and voice in a dozen places at once.