We can tell you how the telephone books. We must say a little about sound. Also, check- STD full form
Soundwaves
Soundwaves consist of small and rapid changes in absentia. The number of changes per second is cold the frequency of the sound. To reproduce sound we need a diaphragm.
Here are the boys making one with a piece of tissue paper and a comb. The paper is the diaphragm and I called diagrams, it responds to the changes in pressure.
To transmit sound as in the telephone, we must connect 2 diaphragms together. Yeah, we are using a torch string. When sound waves hit one of the diaphragms, it vibrates. The vibrations travel along the string to the other diagram which reproduces the sound.
This method has many obvious snags but the basic principles apply to old telephones. In 1874 the inventor of the telephone Alexander Graham Bell wrote” If I could make it better in intensity precise building the reproduction of sound. I should be able to transmit. Also, check- The spo2 full form
Pair of runs
This is a month-long pond the apparatus with which the bell made his words come true. It is connected to another identical instrument by a pair of runs. Let’s see how it is made and how it works.
Firstly there is a diaphragm made of parchment. It is attached to a soft iron strip mounted close to an electromagnet which has a permanent magnet cool. The instrument could be used as either a microphone or as a receiver.
It works by generating cut in from the movement of the strip in the field of the permanent magnet. No battery was needed but the current was weak and the system could not be used to speak over long distances. In the modern telephone, we have overcome this difficulty.
What changes have been made over the years
So let’s see what changes have been made over the years. This is a diagram of a modern microphone. The first point to note is that it is powered by a battery. These 2 wires cat a direct current from the battery and also connect the microphone to the telephone wires online circuit.
The second point to note is that the circuit is completed through a container filled with granules of carbon. We call the instrument a carbon granule microphone. This is the diaphragm. It is made of metal and is attached to one end of the container.
What happens when a sound wave hits the diaphragm.
Now let’s see what happens when a sound wave hits the diaphragm. The wave pushes the diaphragm in and compresses the granules into closer contact. This decreases the resistance and allows more current to flow.
The diaphragm then falls back and the granules move apart again increasing the resistance and reducing the current. Let’s see there’s a game.
When you are speaking these changes occur very rapidly the result is the resistance of the granules. And consequently the strength of the current. There is in accordance with the frequency of the sound received by the microphone. In this way, sound waves turned into a rapidly fluctuating current. Which you see here on the media.
The speech cotton
It may help you to think of this current is made up of 2 parts. The steady current from the battery is like this. And a fluctuating current due to the sound waves. It is only the fluctuating caught. Which we called the speech cotton.
The casual words along the line to the receiver. In the receiver, the current is turned back into sound waves again so that your speech can be hurt. The diaphragm is attached to an iron bar. Which is pivoted. And mounted close to the close of an electromagnet.
The bar is cold a rocket launcher and we use permanent magnetism and electromagnet. In principle, the modern receiver is not unlike the bell’s original but it is very much more sensitive.
What happens when the speech current arrives at the receiver?
Now let’s see what happens when the speech current arrives at the receiver. Each fluctuation of the cut is the attraction of the homage to. Making it and the diaphragm vibrate at the same frequency.
So reproducing the original sound. That is what happens when you speak to your friend on the telephone. So far however we have said nothing about how one telephone is connected to another. Let’s look into this now.
Here is a microphone. Remember it needs direct current from the battery to make it work. Now the receiver. One might expect to connect the microphone battery and receive it in series. So that you can speak to beat the system works but it is wasteful because the battery has to do more work than is really necessary.
The speech current is weakened and we cannot speak over very long distances. For this reason, we connect our telephone system in a different way as we can with the receiver from the speech kind of loan we removed the steady current by connecting the microphone through a transformer.
Transformers
Transformers help us connect telephones because they were part of the fluctuating kind the stock any steady constant. By placing the transformative to the microphone and using it to step up the low input voltage. We can send messages along the line at a higher voltage and therefore over greater distances.
Here to show how they are connected we have put the microphone and receiver close together but in the reality, of course, they may be many miles apart. With this circuit, we can only speak in one direction.
To speak in both directions we could use another identical circuit like this. This method is rather wasteful. However, there is no reason why we cannot use only one pair of the wild by rearranging the connections like this. The microphone and receiver are now coupled together through the transformers at each end.
We also need switches or telephone hooks to break the circuit and save the batteries when they’re not in use. Last year we need bells and they are connected so that they can be wrong even though the switches are open.
Cut to ring the bells is supplied from the telephone exchange which also contains all the equipment needed to connect one telephone with another. Here we have shown all the pots spread out but in reality, apart from the battery, they are boxed together in the mountains with which we are familiar.
We can now see what happens when a call is made. Suppose a wishes to telephone P.. First of all aid must lift the handset. When he does this the switch closes and the signal is sent to the exchange.
The speech content is transmitted
Meanwhile direct current flows in the microphone second ready for a to speak. We are assuming that a is connected to a manual exchange. The signal stays on until the operator announces a by plugging into his number. She now plugs into line B. and makes bees’ bell ring by moving a key.
When Beyonce by lifting her hands as the switch closes. The bell stops ringing and the operator connects a direct to be you can now speak to your friend. 961. Yeah right. You. The correct kind is energizing the microphone.
The speech content is transmitted through the transformers along the line like this. This then is a simple form of the circuit back without which telephones can be connected. In busy places, only one battery is used and that is kept at the exchange.
Of course, there are not just telephones but many hundreds and indeed thousands all connected to the one exchange. The operations necessary to connect one subscribe to another are performed at the telephone exchange either manually.
Wrapping Up
As we have seen more water medically. In every corner to the direct link is established between the corner and the quote. Today we can speak to people on the other side of the world almost as easily as we can my friends around the corner.
We can do so because of the fact that one diaphragm can be made to reproduce the fluctuations of another.
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