How to make BUZZER from RELAY switch

How to make BUZZER from RELAY switch (Introduction)

 Hi, friends, today i will show how to make buzzer out of relay. Relay is nothing but a switch which is controlled by voltage which we provide. Suppose a relay of 5 volts will act as switch if we provide 5 volts and a little above 5 volts. For this reason it was used as a logic switch in earlier days. In the picture the circuit diagram of  relay is shown.Relay is actually single pole double throw(SPDT) switch.

The original is like-

As you can see It has 5 pins. Let us name those pins.
1. The leads to which we provide voltage by connecting them with battery --V1 and V2 (no polarity is concerned ) 
2. The pin 'I' which is the pin through which we send desired input signal. 
3. NC pin(normally closed) with which lead I is shorted when we do not provide voltage. 
4. NO(normally open) lead with which I will be shorted when we provide required voltage between V1 and V2
  The working principle of relay is very simple. When you connect battery, current passes through the coil and activate the electromagnet which will attract the tip shown in the picture to make NO and I leads shorted.

  Now, come to the main point. Things required to make the switch-
1. Breadboard (optional)
2.Relay
3.connecting wire 
4. Battery (according to the rating of relay)
5. battery caps

 Now, you need to check which one is NC and which one is NO pin. Use a continuity tester to test 
which one is NC and NO.Or you can skip this procedure, that no need for continuity test!
Just connect the 'I' pin with V1 or V2 as shown in the picture.

Now, the ultimate step. Connect V1(or V2) with one pole(+ or -) of battery and take the other pole and touch the remaining two pins.If you hear a buzzing sound while touching a pin then the pin will be NC.

Actually what is happening here is that we are providing voltage between V1 and V2 through NC pin. When relay gets proper voltage 'I' will be shorted to NO pin.So there is no voltage between V1 and V2. So 'I' will again be shorted with NC pin which will again force 'I' to short with NO. This process continues and the frequent movement of the lead will produce buzzing sound. 

Here is the video-

How to repair damaged headphone

Hi, friends. We all face problems with damaged earphones.Sometimes no sound comes out of it or one of the speakers stops working. But, headphones get damaged hardly. Main problem occurs due to loose connection. You can fix this with simple tools which you can get any electronics shop.
    1. Soldering Iron, Soldering wire.
    2. Continuity tester (If you have multimeter then you can use it or I will post on how to make continuity tester)
   Now, come to the main point. The circuit diagram of most of the headphones is like that-

  Here the jack has four rings. As there is no standard color coding for earphone, every company has its own coding( even same company changes it for different models of phone! may be to produce artificial crisis!). But when I came across different earphones, I understood one thing that all this earphones have one thing common and that is the first two rings are always for audio output (its color may be RED, GREEN. May vary). The picture underneath is the jack of Micromax E313

Now comes the necessity of continuity tester. If you know how to use it then It's fine, if you don't I will write blog on this topic in future.
 Now, the problem arise due to following causes-
 1. Wire is not connected.
2.Loose connection
3. Wire of the headphone is damaged.

                                    Firstly, open gently the box which has a phone symbol on it. Actually the control circuit is kept here.

 You will find some circuit which is similar to the circuit above.

 If you find SMD resistors, capacitor, don't get panicked just check this, you will find some pleasure-
https://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiW1orZvMvNAhUJqY8KHeTKB1EQjRwIBw&url=http%3A%2F%2Fforums.androidcentral.com%2Fsamsung-galaxy-s4%2F334540-galaxy-s4-headset-mic-button-wiring-schematic-pinout.html&psig=AFQjCNHDomS0Q7E8iT9BsKOCV47ZSvW0iQ&ust=1467229152278450
   Every company has its own style, but the basic circuit remains same. I have found many times a resistor in series with microphone.
   * Now use your continuity tester to test the first half of the circuit, that is from jack to the wire entering into the control circuit.In this way you can also find the colors representing Left,Right audio, microphone and common.Write it down in your copy.(If you have a mobile which is not supporting a headphone, you can change the wires after downloading the required color code of your set from internet) If it passes the continuity test then there is no problem in jack. If it does not then replace the jack( you can buy the jack, it's cheap buddy!).

 Then solder the wires correctly.
   * Now, comes the second part of your earphone that is output of control circuit to speakers. Open those plastic cases carefully and perform continuity test( If you don't want to open the case then open another headphones control box which is working properly and by touching the leads like the picture you can check its functionality. If sound comes out of it, then it is in good condition.

   Note: Some times cutting the wire and soldering it again solves the problem.See below-

  * Any wire which has been detached is easily visible. Solder it properly.

               I hope this will solve the problem, if not then comment. Actually I am a student.These types of "fixing" topics give me pleasure! I will share more topics in future. Thank you,