拾音器（4940）
简介：
Prepolarized Free-field ½-inch Microphone Type 4940 offers significant benefits when used with portable instruments. You can, for example, use small associated instruments with low power consumption. This prepolarized condenser microphone is particularly suitable for both outdoor and industrial environment measurements. It is also suitable for IEC 60651 Type 1 measurements and frequency analysis measurements.
The microphone is capable of withstanding the IEC 68-2-32 1 metre drop test.
Ageing at high temperature and the assembly of the microphone in a clean room environment ensure that the microphone can be used in high humidity environments and still produce reliable results.
The sensitivity can be calibrated at 250 Hz using Pistonphone Type 4228 with ½-inch Adaptor DP 0776. The actuator response can be measured using Actuator UA 0033. The free-field response can be obtained by adding the type-specific, free-field corrections to the actuator response.
技术参数：
电容：14 pF；
直径：1/2 英寸；
动态范围：14.6 - 146 dB；
频率范围：6.3 - 20000 Hz；
固有噪声：14.6 dB A；
-3dB下限频率：4 Hz；
最优：Free field；
极化：Ext. polarized；
压力系数：-0.01dB/kPa；
灵 敏 度：50 mV/Pa；
温度系数：-0.001 dB/ºC；
温度范围：-40 - +150 ºC；
通气：后方。
主要用途：
Sound level meters；
Noise measurements according to IEC and ANSI standards；
Transport noise measurements.