Television is such a device by which we can hear the sound and watch the picture of the speakers on the s cvn from distant place. In 1926, Logy Beard was able to send pictures on television. On that day, the TV actor was a talking doll.
How Television Work:
We know that we can see picture on television along with hearing the sound. To send the sound and picture on television, there are separate transmitters in the transmitting station by which sound and picture can be sent in the form of electromagnetic wave.
Pictures are transformed into electrical signals and then sent with the help of one of the transmitters. With the help of another transmitter, pictures are transformed into electrical signals and then transmitted them in the form of electromagnetic wave. At first, we should discuss sending and receiving the picture. The pictures or the scenery are to be sent has to be converted into electrical signals by the TV camera. This signal is mixed with a high-frequency carrier in the modulation process. Afterwards, it is sent in the form of the electromagnetic radio wave with the help of an antenna. TV set receives electromagnetic carrier wave for the picture with the help of antenna.
Rectifier separates video electrical signal from the carrier wave. This electrical signal is amplified by an amplifier and it is sent to the electron gun. This electron gun is attached to the back of the picture tube of the television. After receiving the video signal, the electron gun shoots the narrow electron beam like a needle. When the electron beam from the electron gun incidents on the fluorescent phosphor screen of the TV, then flash of light is created. With the combination of these bright and dark spots, bright and dark light spots and flashes are created on the TV screen. The picture sent from the camera is seen on the TV screen with the combination of these bright and dark spots. This forms 25 still picture on the TV screen in every second which our eyes see as moving picture.
Colour television: There are no major differences between the basic principles of colour TV and Black and White TV. There are three separate electron guns in the camera of colour television for three basic colours (Red, Blue and Green) .There are also three electron guns in the receiving machine of colour television. The screen of colour television is made of three kinds of phosphor granules. A particular colour illuminates the phosphor granules of that particular colour. Consequently, the screen of a television tube gives red, blue and green light spots. Hence the coloured image becomes visible on the TV screen.
