Tantalum Capacitors Are Used In Audio And Microphone Applications

Aug 30, 2019

With the increasing application of tantalum capacitor in the market, the increase of models and its supply quantity, and the decline of price, many industries are replacing aluminum electrolytic capacitor with tantalum capacitor. Of course, tantalum capacitor also has its own defects. It is not high enough to withstand voltage, which greatly limits the application area of tantalum capacitor. Take the audio circuit for example, the audio circuit usually includes filtering, coupling, bypass, frequency division and other capacitors. How to use capacitors more effectively in the circuit has a great impact on the improvement of sound quality. Tantalum capacitors are used in most coupling capacitors in sound circuits.

The principle of tantalum capacitor is as follows: tantalum is easily oxidized in the air, and people use its oxidation film as medium medium. As tantalum is easily oxidized, tantalum capacitor can automatically "heal wounds", so it is durable and reliable. As the oxide film is very thin, the distance between the two electrodes of tantalum capacitor is very close, with little inductive resistance and very sensitive, so the charging and discharging speed is fast. These characteristics determine that tantalum capacitors are suitable for high frequency, low current and fast response circuits. Therefore, tantalum capacitors are also widely used in satellite circuits that require fast response and high reliability. Tantalum capacitors are very sensitive and fast in charge and discharge, so they are often used in audio circuits of high audio, mainly high audio circuits. By reducing the loss of weak current of high audio, they relatively improve the high pitch and sound quality.

The capacitive microphone has two metal plates, one of which is coated with electret film (mostly polyperfluoroethylene) and grounded, and the other plate is connected to the gate of the field effect transistor. The gate and the source electrode have a diode indirectly, as shown in FIG. 2-4. When electret diaphragm itself with charge and surface charge power for Q, plate between the electric capacity of C, in the head is produced voltage U = Q/C, when by vibration or by air friction, due to the vibration change the distance between the two plates, the capacitance C change, and power Q remains unchanged, it will cause the change of the voltage, the size of the voltage change, reflects the strength of the external pressure, the voltage change frequency reflects the outside the frequency of the sound, this is the working principle of the electret microphone.

Advantages:

Capable of converting sound directly into electrical signals

Capacitive microphone is designed by using the principle of capacitor charge and discharge between conductors, using ultra-thin metal or gold-plated plastic film as vibration film to induce sound pressure, so as to change the static voltage between conductors into electrical energy signal directly, and obtain practical output impedance and sensitivity through electronic circuit coupling.

It can display the characteristics of original sound reproduction

Audio experts in pursuit of "original sound reproduction" for the highest state of sound! Based on the basic design principle of microphones, it is not difficult to find that capacitive microphones not only rely on precise mechanism technology, but also combine with complex electronic circuits to directly convert sound into electrical signals.

It has a very wide frequency response

Vibration membrane is the main component of microphone to induce sound and convert it into electrical signal. The material and mechanism design of vibration film determine the characteristics of microphone sound quality. Since the vibration film of capacitive microphone can be made of very thin material, and the induced sound pressure can be directly converted into audio signal, the frequency response bass can be extended to the ultra-low frequency below 10Hz, and the treble can easily reach the ultrasonic wave of tens of KHz, showing very wide frequency response characteristics!

Ultra-high sensitivity

Because there is no voice coil load on the vibration membrane, it can be designed in a very light and thin way. Therefore, the frequency response is extremely superior and the sensitivity is excellent. It can sense extremely weak sound waves and output the clearest, most delicate and accurate original sound.

Fast instantaneous response characteristics

In addition to determining the characteristics of frequency response and sensitivity of the microphone, the ability of the vibration membrane to respond quickly and slowly to sound waves, namely the "instantaneous response" characteristic, is the most important factor affecting the microphone timbre. The instantaneous response characteristic of the microphone depends on the weight of the vibration membrane. The lighter the vibration membrane is, the faster the reaction speed will be. Capacitive head is very thin and thin vibration film, with extremely fast instantaneous response characteristics, can show clear, bright and powerful timbre and accurate audio and video. In particular, there is no sound dye and "box sound" in the middle and bass, and the high pitch is delicate and clear, which is the most prominent characteristic of the capacitive timbre. It can be clearly seen from the attached figure below that the instantaneous response characteristic of capacitive sound head is much better than that of moving coil.

With ultra-low touch noise characteristics

The touch noise caused by the contact with the palm when using the hand-held microphone mixes the original sound with additional noise, which has a huge impact on the sound quality, especially for the wireless microphone with preamplifier circuit, so the touch noise becomes an important item to judge the advantages and disadvantages of the microphone. From the physical phenomenon, goose feather and copper plate also fall to the floor, goose feather can hardly hear the sound of falling, and the copper plate is very loud, indicating that the lighter material is heavier than the sound of the impact. Similarly, the vibrating membrane of capacitive microphones is relatively light and inherently has the excellent characteristics of "ultra-low touch noise".

It is resistant to falling and impact

The use of microphones will inevitably lead to malfunction or abnormal due to accidental drop and collision. Since the capacitive sound head is composed of light plastic parts and strong light metal shell, the impact force of falling to the ground is small, and the failure rate of damage is low

Small in size and light in weight

Capacitive microphones have the characteristics of small size, light weight, high sensitivity and superior frequency response due to the use of ultra-thin vibration membrane, so they can be designed into ultra-small microphones (commonly known as small bees and ants) for wide application

Best fitted with wireless microphone

Capacitive microphone has the characteristics of the perfect, become the singing sound engineering experts and master's favourite, and wireless microphones in stage or singing karaoke in the home, has become a trend in today's world, wireless microphone for itself can offer bias in condenser cartridge, which has all the advantages of the capacitive microphone, become the era of digital audio, professional audio expert coveted best microphone.