Electric Bell & its works

 

Construction:

An electric bell consists of an electromagnet. One end of the winding is connected to a terminal (T1). The other end is connected to a Spring, which is mounted on a soft iron strip called “Armature.” A rod is attached to the armature with its free end having a small hammer that can strike against the bell. a very light spring is attached to a contract adjusting screw which is joined to the second terminal (T2) by a wire. The electric circuit is completed by connecting the terminals to a batter and a switch.

 

 

Working:

 

When the push button switch is pressed, the circuit gets closed and the armature is attracted towards the electromagnet. The spring also gets detached from the screw. This results in opening the circuit and the electromagnet gets demagnetized. The attraction disappears bringing back the spring to its original position. As soon as the spring touches the screw, the circuit gets closed and the magnet starts to work. It again attracts the armature and this process is repeated as long as the switch is turned on. As a result, the armature vibrates and hammer attached to it strikes the gang. Hence, the bell rings.

 

Developers solve this issue in different ways – someone offers special flashlights that cling to a book, someone builds in a backlight. The latter in the reader will be located “at the edges” of the screen, and therefore will not strain the eyes once again – the only drawback is that it will significantly reduce the device’s endurance, “eating” the battery. The E-ink display has a significantly slower refresh rate than the tablet screen. This parameter does not affect the functions of the book, but precisely because of the speed, the book is not able to reproduce video content, which is within the power of a tablet.