Question

Write any two merits of piezoelectric microphone.

Hint:

While rugged and cost-effective, crystal microphones are highly sensitive to high temperatures and humidity (which can dissolve Rochelle salt crystals) and have a limited frequency response compared to studio condenser microphones.

Answer 1

Step 1: Understanding Piezoelectric Microphones:
A piezoelectric microphone (crystal microphone) operates using the piezoelectric effect. When sound waves strike the diaphragm, they apply mechanical stress to a piezoelectric crystal (such as Quartz or Rochelle salt), which directly generates a proportional electrical voltage.

Step 2: Identifying Key Merits:
Two major advantages of piezoelectric microphones are:

• High Output Voltage Level (High Sensitivity): Because piezoelectric crystals generate relatively large voltages under mechanical stress, these microphones have high output sensitivity. This allows them to output a strong signal that often does not require an additional pre-amplifier stage before being sent to the main amplifier.
• Simple, Rugged, and Cost-Effective Construction: These microphones contain no complex coils, permanent magnets, or external DC bias supplies. This simple design makes them compact, highly durable, structurally robust, and inexpensive to manufacture.