MIL-STD-202-308 Base Document:2015

FOREWORD
1. SCOPE
2. APPLICABLE DOCUMENTS
3. DEFINITIONS
4. GENERAL REQUIREMENTS
5. DETAILED REQUIREMENTS
6. NOTES

Determines the 'noisiness' or 'noise quality' of a resistor in order to determine its suitability for use in electronic circuits having critical noise requirements.

This resistor noise test method is performed for the purpose of establishing the \"noisiness\" or \"noise quality\" of a resistor in order to determine its suitability for use in electronic circuits having critical noise requirements. This method is intended as a standard reference for the determination of current noise present in a resistor, for use in an application with specific current-noise requirements. It is not intended as a general specification requirement. Interference caused by the generation of spurious noise signals in parts tends to mask the desired output signal, thus resulting in loss of information. For low-level audio frequency and other low-frequency circuits, where low-noise parts are used, resistors may become an important source of interfering noise. One source of noise in a resistor is molecular thermal motion which generates a fluctuation voltage termed \"thermal noise\". It is not necessary to determine the magnitude of thermal noise by measurement since the mean-square value of the fluctuation voltage is predictable from Nyquist\'s equation, which shows the mean-square value to be proportional to the product of resistance, temperature, and the pass band of the measuring system. Generally, an increase in fluctuation voltage appears when direct current (dc) is passed through resistive circuit elements. The increase in fluctuation voltage is termed \"excess noise\" or \"current noise\". The magnitude of current noise is dependent upon many inherent properties of the resistor such as resistive material and other factors such as processing, fabrication, size and shape of resistive element, etc. Since there is no apparent functional relationship between current noise and many of these factors, current noise generally cannot be predicted from physical constants. Therefore, it is necessary to measure current noise to determine its magnitude. The method employed in this test has been designed to evaluate accurately the \"noisiness\" or \"noise quality\" of ind...