The **PUM-5250L-R** is a specific model of an omnidirectional electret condenser microphone (ECM) capsule. These components are widely used in consumer electronics, telecommunications, and recording devices due to their small form factor and high sensitivity. --- ### 1. Technical Specifications The following table summarizes the typical electrical and physical characteristics of the PUM-5250L-R: | Parameter | Value | | :--- | :--- | | **Type** | Electret Condenser Microphone (ECM) | | **Directivity** | Omnidirectional (360° pickup) | | **Sensitivity** | -42 ± 3 dB (0dB = 1V/Pa, 1kHz) | | **Operating Voltage** | 1.5V to 10V DC (Standard 2.0V) | | **Current Consumption** | Max 0.5 mA | | **Impedance** | Low Impedance (< 2.2 kΩ) | | **Frequency Range** | 20 Hz – 16,000 Hz | | **Signal-to-Noise Ratio** | > 58 dB | | **Dimensions** | Approx. 6.0 mm (Diameter) x 5.0 mm (Height) | | **Connection Type** | Solder Pads (L-type often refers to Lead wires) | --- ### 2. Internal Electronic Structure The device operates on the principle of a variable capacitor. Internally, it consists of several key layers: 1. **Electret Diaphragm:** A thin plastic film with a permanent static charge. 2. **Back Plate:** A rigid metal plate that forms the other half of the capacitor. 3. **JFET (Junction Field Effect Transistor):** Because the capsule has extremely high impedance, an internal JFET acts as an impedance converter/pre-amplifier to make the signal usable for standard circuits. 4. **Housing:** An aluminum can that provides structural integrity and EMI (Electromagnetic Interference) shielding. --- ### 3. Application Circuit To use the PUM-5250L-R, you must provide a "Bias Voltage" through a resistor. Below is a standard wiring diagram representation: ```text [ VCC (+2V to +10V) ] | [ R1: 2.2kΩ Load Resistor ] | +----[ C1: 1uF to 10uF Coupling Cap ]----> [ Audio Out ] | [ Mic Pin + ] [ Mic Pin - ] | [ GND ] ``` ### 4. Key Features * **High Sensitivity:** Capable of picking up faint sounds at a distance. * **Small Footprint:** Ideal for integration into headsets, smartphones, and IoT devices. * **Stability:** High resistance to vibrations and temperature fluctuations within standard operating ranges. ---