Electric Buzzer
The buzzer
operates on the principle of electromagnetism. The electromagnet is made by
coiling copper wire around a nail and connecting both of the ends to the
battery. Here, I have connected one of its ends to the negative terminal of a
battery while the other end is connected to a blade which gets connected to the
positive terminal of the battery by the paperclip. When the connection is
completed the sound of the buzzer will be heard.