Microphone for the computer with their own hands
It is very difficult to get along without a computer microphone now; you cannot use voice search without it, you will not be able to chat with a friend over video. However, the built-in microphones are not in all computers, besides, often, they have not very good sensitivity. To solve this problem, you can simply - collect the microphone yourself.
The circuit is extremely simple; it contains only two resistors, two capacitors, a transistor and an electret microphone cap. The transistor can be applied to almost any low-power n-p-n structures, for example, KT3102, BC547, BC337. An electret microphone can be obtained, for example, in a broken headset, handset, or else you can buy it in a store of radio components. This element will greatly depend on the sensitivity of the microphone, so it is advisable to take a few and check which one is best. The advantage of this scheme is that it uses phantom power. Those. the sound signal is transmitted through the same wires as the power supply. If you take a voltmeter and measure the voltage at the microphone input of the computer, there will be about 3-4 volts.When connecting a microphone circuit, this voltage should sink to the level of 0.6-0.7 volts, thus, an external power source will not be needed and there will be no extra wires in the workplace.
The scheme contains a minimum of parts, so it can be assembled by mounting. But, adhering to traditions, I have etched out a miniature printed circuit board. Tracks can even be drawn with a marker or nail polish. Several photos of the process:
A microphone cap is soldered to one end of the board, and a shielded wire is connected to the other end. Please note that the wire must be with a screen, otherwise the microphone will be terrible to fade. Wire braiding is soldered to the minus, and two internal conductors are connected and soldered to the output of the circuit. Be sure to observe the polarity of the microphone capsule, otherwise the circuit will not work. One of his conclusions goes to a minus, and the second to a plus. Determining the polarity is very simple - you need to ring the findings with the metal case of the capsule. The conclusion that connects to the body is negative.
Board with soldered parts for ease of use should be placed in a suitable case. SinceSince the board has a narrow elongated shape, then an ordinary ballpoint pen can be used as a case. To do this, you need to pull out the writing rod from it and check whether the board is suitable for the width. If the circuit is assembled by mounting, then it can be given any shape and there will be no problems with capacity. In addition to the pen, any elongated object is well suited, be it a marker or a simple plastic tube.
The board fits inside, the microphone should slightly stick out of the case. The wire is output from the other side. For reliability, the board along with the wire can be glued inside the case. The tip of the handle needs to be cut so that the hole becomes wider and the sound waves calmly reach the microphone cap.
At the other end of the wire, solder the jack 3.5 plug to connect to the microphone input of the computer. On this assembly of a computer microphone is finished, you can turn it on and check the sound quality.