### POM-1547S-R: Technical Overview The **POM-1547S-R** is a high-sensitivity, omnidirectional electret condenser microphone (ECM) capsule. It is designed for picking up sound from all directions and is commonly used in consumer electronics, telecommunications, and audio recording devices. --- ### 1. Key Technical Specifications The following table summarizes the primary electrical and physical characteristics of the component: | Feature | Specification | | :--- | :--- | | **Type** | Electret Condenser Microphone | | **Directivity** | Omnidirectional | | **Sensitivity** | -47 ± 3 dB (0dB = 1V/Pa) | | **Operating Voltage** | 2.0V (Standard), 10V (Maximum) | | **Current Consumption** | 0.5 mA (Max) | | **Frequency Range** | 50 Hz ~ 12,000 Hz | | **Signal-to-Noise Ratio** | > 60 dB | | **Impedance** | 2.2 kΩ | | **Dimensions** | Approx. 6.0mm (Diameter) x 5.0mm (Height) | | **Connection Type** | Solder Pads | --- ### 2. Physical Construction The POM-1547S-R consists of several critical layers within its small cylindrical aluminum housing: 1. **Diaphragm:** A thin, metalized plastic film that vibrates in response to sound waves. 2. **Back Plate:** A stationary plate that, along with the diaphragm, forms a capacitor. 3. **Electret Layer:** A permanent charge material that eliminates the need for a high-voltage external power supply. 4. **Internal FET:** An integrated Field Effect Transistor (JFET) that acts as an impedance converter, transforming the high-impedance signal from the capsule into a usable low-impedance output. --- ### 3. Application Circuitry To use the POM-1547S-R, a simple biasing circuit is required. The microphone acts as a variable current source. ```mermaid [Vcc] --- [Resistor (2.2k)] ---+--- [Microphone (+)] | [Capacitor (10uF)] --- [Audio Out] | [Microphone (-)] --- [GND] ``` * **Load Resistor ($R_L$):** Usually 2.2kΩ, matched to the microphone's internal impedance. * **Coupling Capacitor:** Blocks the DC bias voltage from entering the amplifier stage, allowing only the AC audio signal through. --- ### 4. Common Use Cases * **Telephony:** Handsets and speakerphones. * **Computing:** Laptop internal microphones and headsets. * **IoT Devices:** Voice-activated assistants and smart home sensors. * **Audio Recording:** Portable voice recorders and ambient noise sensors. ---