The structure and classification of the microphone
The microphone is a start of a conversion from an acoustic signal to an electrical signal. Because this signal is very weak, the internal resistance is very high, can not be used directly, so also to carry out impedance conversion and amplification. FET FET is a voltage control element, the output current of the drain is controlled by the source and gate voltage. Since the two poles of the capacitor are connected to the S pole and the G pole of the FET, a corresponding change in Δv is applied between the S pole and the G pole of the FET, and the drain current I of the FET generates a change in ΔID So that the amount of change in the current on the resistance RL to produce a ΔVD changes in the amount of change in the voltage can be output through the capacitor C0, the voltage change is caused by the sound pressure, so the entire microphone to complete A sound of the conversion process.
1, from the working principle points: carbon particles, electromagnetic, capacitive, electret condenser, piezoelectric crystal, piezoelectric ceramic, silica and so on.
2, from the size of the points, the electret can be divided into several kinds.
Φ9.7 series Φ6 series Φ5.8 series of products
Φ4.5 series Φ4 series Φ3 series of products
Each series has a different height
3, from the direction of the microphone, can be divided into omnidirectional, one-way, two-way (also known as denoising)
4, from the polarization method points, diaphragm type, back pole type, front pole type
From the structure points can be divided into gate spot welding, gate crimping, pole ring connection and so on
5, from the external connection points
Common solder joint type: L type
With pin type: P type
Concentric: S type
With omni-directional MIC, diaphragm-type pole ring connection as an example
1, dust net: to protect the microphone, to prevent the dust fell on the diaphragm, to prevent external objects piercing diaphragm, there is a short time waterproof.
2, the shell: the support of the entire microphone, and other pieces enclosed in the shell, the microphone is the grounding point, you can also play the role of electromagnetic shielding.
3, diaphragm: is a sound-electric conversion of the main parts, is a tense Teflon plastic film attached to a thin metal ring, the film and metal ring contact with a layer of thin metal layer, The film can be charged with charge, but also to form a variable capacitor of an electrode plate, and can vibrate the plate.
4, gasket: support the distance between the capacitor plate, leaving a gap for the diaphragm vibration to provide a space, thus changing the capacitance.
5, the back plate: the other electrode of the capacitor, and connected to the FET (FET) G (gate) pole.
6, copper ring: connecting the plate and the FET (FET) G (gate) pole, and play a supporting role.
7, the cavity: fixed plate and pole ring, so as to prevent the plate and pole ring short circuit (FET (FET) S (source), G (gate) pole short circuit).
8, PCB components: equipped with FET, capacitors and other devices, but also play a fixed role in other parts.
9, PIN: Some of the microphone with a PIN on the PCB (feet), PIN and other PCB can be welded together, from the other front to connect, the back of the structure is also slightly different.
Above we are talking about the content is for the structure of the microphone and the part of the description of the microphone, the description is not very accurate in place, we hope that a lot of support and complement, let us work together to do a good job, This is our mission.