How to Build a Simple Microphone Circuit

Now we're going to build the simplest microphone circuit that can be built so that you can use the microphone to record speech on any audio software on a computer. All we do for this experiment is take a microphone and connect it to a 3.5mm plug. Afterwards, this microphone will be able to work on any standard computer.

Parts Needed
-Any Type of Microphone
-3.5mm plug

For this project, any microphone can work. Whether it's unidirectional or omnidirectional doesn't matter. We are just using it for basic recording. The sensitivity of the microphone doesn't really matter either. The higher the sensitivity would be the better because it would record a stronger signal, but regardless of sensitivity, we should still record a signal.

So now we take the microphone and solder two wires onto them. The usual convention is to use black wire for ground and red wire or any other light color for the Mic Positive Connection.

Soldering Microphone

Be careful while soldering the microphone with the jumper wires because if you apply too much heat to the microphone, it will be destroyed and useless; and then it will not record anything. If you can, buy a microphone that already has the wires preattached. This is good so that you don't accidentally destroy the microphone or if you don't have a soldering iron to solder.

Now that this is done, all we need to do now is connect the 3.5mm plug to the microphone. The type that you see being used with this project is a mono plug; it only has two contacts. However, a stereo 3.5mm plug can also be used. For this experiment, it doesn't matter. The 3.5mm plug may come in many fashions. It may be a 3.5mm male to male plug, a 3.5mm male to female cable. We are not interested in the other side, only the male side. What we're going to do is take the 3.5mm plug and cut it at any part of the wire. This should expose two wires, a wire which represents the positive side of the male plug and a wire which represents the ground of the male plug.

Clipping 3.5mm Jack

Now is the last part: to solder the microphone to the 3.5mm plug. This is shown below:

Simple Easy Microphone Circuit

This is now the completed circuit. I'll admit, it's not beautiful, but this project is just to teach you how you can build a microphone to work on a computer. If you want, you can find ways of crafting it so that it looks better but here we're just explaining the functionality.

As you may know or may not, all microphones need power in order to work. How does this microphone get power? The answer is, it gets power from the computer when it's plugged into it. The 3.5mm plug draws power from the computer which then powers the microphone so that it can work. This is the same way how USB-powered devices work, which are USB devices which don't need a separate power plug to operate, but draws power from the USB through the computer. The same applies here for our 3.5mm plug. You also may know (or not) that microphones need amplfication to give out any reasonable strength of signal. How does this microphone get amplified? Through the sound card in the computer. If it wasn't for the sound card in the computer, when you speak into the microphone, it would give out such a faint signal that barely anything would get recorded. When you plug the 3.5mm plug into the computer, the plug now has connection with the sound card in the computer and our desired signals recorded by the microphone are amplified by the sound card, so that we can record signals with good enough strength to get a decent volume level. So this is how this microphone works.

Hope you learned things and enjoyed this experiment.

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