This is a CUI CMC-9745-44P omnidirectional 9.7mm diameter condenser microphone with PCB leads that are breadboard compatible.
- Microphone Condenser CUI CMC-9745-44P
KEY FEATURES OF MICROPHONE CONDENSER 9.7MM:
- 20 Hz – 20 kHz frequency range
- -44dB +/- 3dB sensitivity
- 3-10VDC operating voltage
- 2.2kOhm output impedance
This is a miniature condenser microphone that is used for converting acoustical energy (sound) into electrical energy. Condenser is the old term for capacitor and these microphones use a capacitor type construction to detect sound. When sound waves hit the microphone diaphragm, it changes the distance of the two capacitor plates and therefore the capacitance which in turn changes the electrical output of the microphone . Condenser mics are more sensitive and have greater dynamic range than similar dynamic microphones.
Condenser microphones are powered, so they require a working voltage of 3 – 10VDC along with a couple of external components including a load resistor and a capacitor to AC couple the output.
This microphone has two 4.5mm long PCB leads on the back with standard 0.1″ (2.54mm) spacing. They are long enough to work well in a solderless breadboard.
Terminal 1 is the output and is connected to the power source via a resistor with a value of 2.2K.
A series capacitor with a value of approximately 1uf – 10uF is placed on the output. This output may be fed into an audio amplifier of some type to boost the signal or feed the analog input of a microcontroller.
Terminal 2 is connected to the system ground.
Our Evaluation Results:
These mics work well for adding sound detection to a project.
Below is a scope capture using the circuit shown in the schematic. Power to the mic is 5V and the scope is set for 10mV/div. Input is a whistle
|-44dB ± 3dB
|3V typical, 10V max
|Dia x H
|9.7 x 4.5mm (0.382 x 0.177″)