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Origins and History of Type-Type of Microphones (PART 2)

(Our Tech Blog) This post continues my previous post. If you have not read it silhkan read on Origins and History of Type-Type of Microphones (PART 1)

4. capacitor microphone
capacitor microphone

The capacitor microphone is a microphone made ​​of a metal diaphragm, is attached to a metal plate static with very close distance, so that both isolated and resembles the shape of a capacitor. The existence of sound vibrations cause the diaphragm to move. Diaphragm which moves lead to a change in separation distance between the diaphragm with a static plate so that the resulting change in capacitance value. This capacitor microphones require a constant DC voltage which is connected to a diaphragm and passes through a static plate load resistor, so the microphone voltage can vary with changes in air pressure caused by sound vibrations.

5. Elektret microphone

Elektret microphone

Elektret microphone is a special type of capacitor microphone which has its own sources of content that does not require external power supply. The source charge comes from a mass storage device is made ​​of Teflon. Teflon material is processed in such a way so as to capture the charges remain in large quantities, then keep it for an unlimited time. Thin layer of Teflon on a metal plate attached to the static and contain negative charges in large numbers. Charges are trapped on one side, which led to the electric field in the slit-shaped capacitor. Sound vibrations that are changing the air pressure in it so it makes the distance between the diaphragm and the metal plates are also changing static. As a result, the capacitance change and the terminal voltage of the microphone was also changed.

6. piezoelectric microphone

piezoelectric microphone

Piezoelectric microphone is a microphone made ​​of crystalline active ingredient. This material may cause the voltage itself while capturing the vibrations from the outside so it does not require power supply. How it works is that the crystal is cut to form an incision in certain fields, then attached to the electrodes or plates so it will show piezoelectric properties. Crystal will change shape when you get a pressure so that the charge transfer will occur shortly in the crystal structure. Charge transfer results in a potential difference between the two plates of the slab. Interestingly, these crystals can be directly received sound vibrations without having to be formed into a diaphragm, so the response frequency will be better than other microphones, although the level of output is much lower, at less than 1 mV.

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