What Is A Microphone PCB?

Printed circuit boards, or PCBs, have gained much popularity since they became adoptable for making general electronics. In today’s time, one can use the PCB for making microphones. In this article, we will talk about what microphone PCB is about. We will also discuss the types of microphone PCBs and how you can enhance their uses.

What Is Microphone PCB?

It is loosely translated to a circuit board primarily dedicated to microphone use. On its part, a 

microphone is an instrument that converts sound waves into electrical energy. This conversion of the electrical signal is available in different variations, such as:

• Amplification of signals as an analog signal.
• Performing digital conversion of the electrical signal into the signal that digital audio devices such as laptops and computers can process.

How Does Microphone PCB Work?

The simplest explanation of how the microphone PCB works is by understanding the combination of the microphone with the PCB. In other words, the microphone PCB has an integrated electret microphone.

With the PCB working as the microphone’s architectural backplate, it helps reduce the number of electrical components required for making a microphone. Rather than adding individual components to the microphone, those are added to the PCB.

Types Of Microphone PCB

Today, different types of microphones are being used. They are also made for applications like picture motions, telephones, hearing aids, megaphones, public address systems, and sound recording.

These mics are also used for the following purposes, such as:

• Television and radio broadcasting.
• Live audio engineering.
• Recorded audio engineering.
• Two-way radios.
• Computer usage such as VoIP, speech recognition, and voice recording.

Several types of microphone PCBs are powered by different technologies, such as:

• Condenser microphones or electret condensers.
• Micro Electrochemical Systems.

That being said, we will now explore the different details of different types of modern PCBs powered by the PCBs.

• Condenser Microphones

Condenser microphones are amongst the oldest microphones, as their first version was made by EC Wente in 1916. Today, condenser microphones are optimized for modern usage, with most having PCBs for holding the components together.

The following explains how condenser microphones work:

• The diaphragm serves as one plate of the capacitors. It is because the condenser microphone may work as a capacitor, which is why it is also known as the capacitor microphone.
• In the condenser microphones, the vibration produces changes in capacitance, and it is because of the inverse proportion of the distance between the plate’s capacitance.
• The audio vibrations change the distance between the plates.

There are different categories of condenser microphones, such as:

• DC-Biased Condensers: this type of microphone has maintained voltages and is changed due to the vibrations in the air.
• Electret Condenser: it is a technology that helps with the construction of modern microphones and also works as a condenser microphone.
• RF Condensers: these microphone types have low radio frequency voltage and are generated by the low-noise oscillator.
• Microelectromechanical Systems 

It is another technology that helps with producing modern microphones, especially with integrating PCBs. They are also called silicone microphones or mic chips; the MEMs works as tiny building block or base of modern microphones.

The following explains how the microelectromechanical systems or MEMs stack up:

• The first process is directly etching the pressure-sensitive diaphragm into the silicon wafer. The microelectrochemical systems process the techniques that are used for this purpose.
• After that, the integrated preamplifier is added.

From optimization and architecture, there is no doubt that MEMs are becoming more popular.

The following are the working principles:

• As the secondary semiconductor fails, the MEMs perform similarly to the audio amplifier. In essence, it helps convert the switch capacitance to the electric signal.
• The sound pressure waves are made with the microelectromechanical partition.

How Do MEMs Microphones Work?

It is necessary to go through the basics to understand how the MEM mics work. According to microphone PCB manufacturers, initially, MEM-related components are positioned at the top of the PCB. They are covered with a mechanical cover and are used for protecting the components.

The following step is creating the case’s hole. It allows sound to penetrate the microphone. The locations for the hole are:

• The top-ported hole design is used if the mic is at the top of the case.
• The bottom-ported hole is located in the mic and within the PCB.

The MEMs Construction

The best way to make the microelectromechanical type of mic is by designing the mechanical diaphragm and mounting the structure; it is made on the semiconductor die.

The Structuring Of Semiconductor Die

The initial semiconductor die is the foundation for holding and hosting the mounting structure and the mechanical diaphragm. There is a secondary die that is needed for the audio preamplifier. In this case, the secondary die will be used to convert MEMs capacitance to the corresponding electric signal. 

Other Mic PCB Types

Other than the MEMs and condenser, several other mics also exist. Some of them are recalled from the way back, such as retro microphones. Other types are:

• Carbon.
• Plasma.
• Piezoelectric. 
• Dynamic.
• Ribbon.
• Wireless microphones.

Retro Microphone PCB

As the name suggests, it is a vintage microphone PCB type – in other words, it has been in use for several years. This microphone type is classified under the wider ribbon microphone – it uses a thin and corrugated ribbon suspended in the magnetic field.

Ribbon mics function by enforcing the ribbon’s electrical connection to the microphone’s output section. It is then followed by generating electrical signals through the vibrations inside the magnetic field.

There are several reasons why the vintage microphone PCB is relevant:

• Retro mics are used as the bidirectional method of sound detection, wherein the sound is dedicated from both sides of the ribbon. 
• The sound-production capability of the vintage microphone PCB is at par with modern microphones. 
• The vintage mic PCB is best for many people, ranging from circuit board engineers to recording artists and audiophiles.

How To Choose Microphone PCB?

When it comes to choosing the microphone PCB, know that it is not limited to the body parts of the microphone. The choice will be between MEMs and Electret Microphones. Following are the comparison between the ECM and MEM mics based on their differences:

• Consider The Use Case

The primary and first difference between the MEM and ECM modern PCB mic technologies is based on the application. Although the MEM is becoming much more popular in mic uses, there are several cases in which it is not required. The primary example is the prioritization of the ECM over the MEM when the use case is to upgrade the existing design of the mic PCB. 

• Does Microphone PCB Designs Are Compact?

The microphone PCB manufacturer stated that they make the MEM PCB design to make mics needed for space-oriented applications. The condensed or compact designs are attributed to the following optimizations:

• Including digital and analog circuits to the mic construction.
• A reduction in the circuit board area.

Conclusion

PCBs are used for making different types of microphones as mentioned above. With the right comparison of MEM and ECM technologies, you can make the right choice. Overall, ensure that the technology adapts to your use case and that the final design supports an upgrade.