Electrec Microphone
Introduction Electrec Microphone:
The sound sensor acts like a microphone (microphone). It is used to receive sound waves and display a vibrating image of sound, but it cannot measure the intensity of noise. The sensor contains a sound-sensitive condenser electret microphone. Sound waves cause the electret membrane inside the microphone to vibrate, resulting in a change in capacitance and a corresponding small voltage. This voltage is then converted into a voltage of 0-5V, which is received by the data collector through A/D conversion and transmitted to the computer.The sound sensor acts like a microphone (microphone). It is used to receive sound waves and display a vibrating image of sound, but it cannot measure the intensity of noise. The sensor contains a sound-sensitive condenser electret microphone. Sound waves cause the electret membrane inside the microphone to vibrate, resulting in a change in capacitance and a corresponding small voltage. This voltage is then converted into a voltage of 0-5V, which is received by the data collector through A/D conversion and transmitted to the computer.
The other side of the diaphragm is separated from the metal plate by a thin insulating lining. In this way, a capacitor is formed between the gold-distilled film and the metal plate. When the electret diaphragm encounters sound wave vibration, it causes the electric field across the capacitor to change, resulting in an alternating voltage that changes with the sound wave. The capacitance between the electret diaphragm and the metal plate is relatively small. Therefore, its output impedance value is very high, about tens of megaohms or more. Such a high impedance cannot be directly matched to an audio amplifier. Therefore, a junction FET transistor is connected to the microphone to perform impedance transformation.FETs are characterized by extremely high input impedance and low noise figures. Ordinary FETs have three poles: active (S), gate (G), and drain (D). A dedicated FET is used that combines a diode between the internal source and gate. The purpose of connecting diodes is to protect FETs from strong signal impacts. The gate of the FET is connected to the metal plate. This results in two output lines for the electret microphone. That is, source S, generally with blue plastic wire, drain D, generally with red plastic wire, and braided shielded wire connected to the metal shell.
Spceifications:
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converted into a voltage of: 0-5V
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computer provides about: 2.3V
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needs : 2.2V
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the positive side to the: 2.2KO
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The other end of the: 2.2KO
Circuit Operation:
The circuit starts with the electret microphone. As stated, the microphone needs power in order to operate. This electret microphone, in particular, needs 2.2V of power in order to operate. Since the microphone port of a computer provides about 2.3V of power, this will perfectly power the electret microphone. You can connect jumper wires from the 3.5mm audio plug cable and connect the positive side to the 2.2KO pull-up resistor and connect the negative side to the ground terminal of the microphone. 'The other end of the 2.2KO resistor then connects to the anode of the microphone. This resistor serves as a pull-up resistor so that the microphone receives the voltage it needs to power on.The only other component in the circuit is the 100µF capacitor. As stated before, this serves to block DC from appearing on the output. The DC voltage is only for biasing power to the microphone. It should not appear on the output sound signal. To block the DC and allow only the AC sound signal to pass through to output, we place a capacitor in series with the output of the microphone.With all these connections in place, the circuit should work. If you plug the 3.5mm audio plug into the microphone port of the computer and do a sound recording, you just get very good output recording.
There is disclosed a microphone, a circuit, and a method. A microphone capsule may include an electret microphone and a field effect transistor (FET). A floating DC voltage source may have a first end connected to a drain terminal of the electret microphone capsule and a second end. A load resistor may be connected between the second end of the floating DC voltage source and a source terminal of the electret microphone capsule. A voltage follower may have an output connected to the source terminal of the electret microphone capsule and the first end of the floating DC voltage source. A coupling capacitor may couple an audio signal from the source terminal of the electret microphone capsule to an input of the voltage follower.
An electrostatic microphone, also commonly called a condenser microphone, contains a fixed plate and a flexible diaphragm that collectively form a parallel plate capacitor. The diaphragm moves in response to incident acoustic waves, thus modulating the capacitance of the parallel plate capacitor. A polarizing voltage must be applied via a high value load resistor to charge or polarize the parallel plate capacitor. Variations in the capacitance in response to incident acoustic waves may then be sensed as modulation of the voltage across the capacitor.An electret microphone is a variation of an electrostatic microphone in which at least one of the fixed plate and the diaphragm include a permanently charged dielectric layer. The presence of the permanent charge obviates the need for a polarizing voltage source to charge the parallel plate capacitor. Electret microphones are used in many applications, from high-quality sound recording to built-in microphones in consumer electronic devices. Nearly all cell-phones, computers, and headsets incorporate electret microphones.
Electret microphones are commonly produced in the form of a “capsule” containing the parallel-plate capacitor microphone and a circuit or preamplifier to transform the high impedance of the parallel-plate capacitor microphone to a lower impedance value. As shown in FIG. 1A, an electret microphone capsule 105 may include an electret microphone EM and a field-effect transistor (FET) Q1 having gate (G), source (S), and drain (D) contacts. A high value (for example, greater than 1 Gigohm) resistor R1 between the gate and drain contacts may be provided or intrinsic to the FET Q1. Although not shown in FIG. 1A, the FET Q1 will have intrinsic parasitic capacitances between the gate, drain, and source contacts and intrinsic parasitic resistances at each of the gate, drain, and source contacts. The values of the parasitic capacitances and resistances may depend, to some.
An audio signal voltage applied to the gate of the FET Q1 by the electret microphone EM will be output from terminal T2 without amplification. The audio signal output at terminal T2 may be coupled to an input of a voltage follower 215 through a coupling capacitor C1. A voltage follower is a circuit that provides an output voltage that dynamically follows an input voltage, which is to say that a change in the input voltage results in a corresponding change in the output voltage. The gain of a voltage follower, defined as the ratio of the change in output voltage to the change in input voltage may be equal to or slightly less than one. There may or may not be a DC voltage offset between the output voltage and the input voltage of a voltage follower. extent, on the voltages imposed between the contacts of the FET.
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How the Eletrec Microphone Work:
Unfortunately, ECM capsules have an issue of extremely high impedance at their output. They should, thus, be in a position to maintain high impedance to prevent leaking of stored charge crossway the plates.An impedance converter (a JFET) effectively removes audio signals from an ECM capsule.Gate (G) is the high-impedance input, and it receives an output signal from the ECM capsule without degrading it.The power supply of JFET is from an external power supply such as DC biasing or phantom power. It subsequently causes an electric current to flow through the source (S) and drain (D) terminals. The wind has low impedance and hence, can be the final mic output.In summary, input signals can control output signals. Therefore, a high-impedance call through the gate-source JFET terminals can control the low-impedance motion at the source-drain terminals.
An electret microphone mainly consists of a diaphragm, a couple of electrodes and an in-built JFET.The diaphragm is made of thin Teflon material and is also termed as “electret” and hence the name electret MIC.This electret has a fixed charge (C ) and is embedded between the two electrodes.The electret along with the two electrodes takes the form of a sensitive variable capacitor whose outer surface responds to sound vibrations, giving rise to a varying capacitance across the two electrodes.Sound waves in the form of air pressure moves one of the electrodes facing the open side of the MIC, causing effective variations across the capacitive plates .The instantaneous value of the varying capacitance of the MIC becomes directly proportional to the sound pressure hitting the electret at that instant.
Electret microphones are a type of condenser microphone that use a permanently charged material called an electret to generate an electrical signal from sound waves. The electret is a thin film of a ferroelectric material that has been polarized to create a permanent electric field. This electric field acts as a backplate for the microphone, which is the stationary plate in a condenser microphone that is charged with a voltage.When sound waves enter the microphone, they cause the electret to vibrate, which changes the distance between the electret and the backplate. This change in distance causes a change in capacitance between the two plates, which in turn generates an electrical signal that corresponds to the sound wave.The latest point of view on electret microphones is that they are a cost-effective and reliable option for many applications, including consumer electronics, telecommunications, and medical devices. They are also widely used in hearing aids and cochlear implants, where their small size and low power consumption make them ideal for implantable devices.In recent years, there has been a growing interest in using electret microphones for environmental monitoring and acoustic sensing applications. These applications require high sensitivity and low noise, which can be achieved with electret
Frequently Asked Questions
What is the principle of electret microphone?
An electret condenser microphone (ECM) consists of a very light diaphragm (moving plate) and back plate (stationary or static plate) and has a permanent charge implanted in an electret material to provide polarizing voltage.
How do passive microphones work?
Passive microphones, also referred to as unpowered or dynamic microphones, do not require external power sources to function. They rely on electromagnetic induction to convert sound waves into electrical signals without the need for additional amplification circuitry.
How does a microphone hear sound?
A microphone converts sound into a small electrical current. Sound waves hit a diaphragm that vibrates, moving a magnet near a coil. In some designs, the coil moves within a magnet. Other microphones, such as condenser microphones, work on the principle of capacitance.
What is the voltage of a microphone?
Microphone or “mic” level is in the region of 0.001 volts (1 millivolt) to 0.01 volts (10 millivolts). This voltage range may also be expressed as -60 dBV to -40 dBV. This is the signal level that comes out of a typical microphone when someone speaks into it at a close distance.
What is microphone in mobile?
A microphone is a device that translates sound vibrations in the air into electronic signals and scribes them to a recording medium or over a loudspeaker. Microphones enable many types of audio recording devices for purposes including communications of many kinds, as well as music vocals, speech and sound recording.
