3. Induction coil, bell, line wires, etc.
4. Action of the whole device.
Exercises
1. State three important electrical laws or principles that are employed in the operation of the telephone. What is the application of each?
2. Connect the binding posts of a telephone receiver with a sensitive galvanometer and press on the diaphragm of the receiver; a deflection of the galvanometer will be noticed. Release the diaphragm and a reflection in the opposite direction is seen. Explain.
3. Is the current passing through the transmitter the one going to the receiver of the instrument? Explain.
4. Does the receiver at the telephone used by a person repeat the speech of the person? Explain.
5. How many 0.5 ampere lamps can be used with a 6 ampere fuse?
6. Why is it necessary to have a rheostat connected in series with a stereopticon or moving picture machine while a rheostat is not used with arc lights out doors?