What exactly are the microphone components of sound level meters used in the home?
The receiving component of the domestic sound level meter is a microphone. It converts the acoustic signal into an electrical signal. After amplification, filtering, attenuation, weighting and a certain degree of circuit damping, it can provide a quantitative measurement of the measured noise according to four standard binning regulations: fast, slow, pulse and hold. Indication.
The microphone converts the sound into an electrical signal, and then the preamplifier changes the impedance to match the microphone to the attenuator. The amplifier adds the output signal to the weighting network, weights the frequency of the signal (or connects an external filter), and then amplifies the signal to a certain amplitude through the attenuator and amplifier, and sends it to the effective value detector, which is displayed on the indicator meter. The numerical value of the noise level is given above.
A microphone is a device that converts sound pressure signals into voltage signals. It is also called a microphone. It is the sensor of a sound level meter. Common microphones include crystal, electret, moving coil and condenser.
1. The moving coil microphone is composed of a vibrating diaphragm, a movable coil, a permanent magnet and a transformer, etc. Sound level meter. The vibrating diaphragm begins to vibrate after being subjected to sound wave pressure, and drives the movable coil installed with it to vibrate in the magnetic field to generate induced current. This current changes according to the amount of sound wave pressure the vibrating diaphragm is subjected to. The greater the sound pressure, the greater the current generated; the lower the sound pressure, the smaller the current generated.
2. The condenser microphone is mainly composed of a metal diaphragm and closely spaced metal electrodes. It is essentially a flat capacitor. The metal diaphragm and the metal electrode constitute the two plates of the flat capacitor. When the diaphragm is affected by sound pressure, the diaphragm deforms, causing the distance between the two plates to change, thus changing the capacitance. The voltage in the bit measurement circuit also changes, realizing the function of converting the sound pressure signal into a voltage signal. Condenser microphone is an ideal microphone in acoustic measurement. It has the advantages of large dynamic range, flat frequency response, high sensitivity and good stability in general measurement environments, so it is widely used. Since the output impedance of the condenser microphone is very high, impedance conversion needs to be performed through a preamplifier. The preamplifier is installed inside the sound level meter close to where the condenser microphone is installed.
