MK:437 & MK:438 Outdoor Microphone
Page 10
Current consumption is less than 100mA. Connection of the power supply must be
made as specified in the connections above.
Output Voltage
The output voltage provided by the MK:438 is determined by the sensitivity of the
microphone capsule specified. The nominal output voltages for the Cirrus Research plc
Class+ capsules are specified below:
Capsule
Nominal Output Voltage
MK:224 Class 1+
50mV/Pa
MK:226 Class 1
37mV/Pa
MK:216 Class 2+
37mV/Pa
MK:215 Class 2
37mV/Pa
For example, a 94dB Acoustic Calibrator will generate a Sound Pressure of 1Pa, giving
the nominal output levels specified above.
Please note that microphone capsules differ in sensitivity between units of the same
type. Care should be taken to ensure that noise measurement systems are calibrated
before use to ensure accurate measurement.
The output impedance of the system is less than 1Ù and the output is current limited to
30mA.
