Significance and Use The current gain of a transistor is basic to its operation and is its single most important parameter. Ionizing radiation, that is, gamma radiation due to a nuclear burst, will degrade the current gain due to lifetime damage in the bulk material. Degradation of gain will be greatest immediately following a burst of ionizing radiation and the gain will rapidly recover to a quasi steady-state value. Defect annealing may continue for weeks but usually the current gain recovery is small or negligible. This method provides a procedure that does not require special-purpose test equipment. This method is suitable for use for specification acceptance, service evaluation, or manufacturing control.Scope1.1 This test method covers the measurement of common-emitter d-c current gain (forward, hFE, or inverted, hFEI) of bipolar transistors, for which the collector-emitter leakage current, ICEO, is less than 10% of the collector current, IC, at which the measurement is to be made, and for which the shunt leakage current in the base circuit is less than 10% of the base current required. 1.2 This test method is suitable for measurement of common-emitter d-c current gain at a single given value of test transistor collector current or over a given range of collector currents (for example, over the range of the transistor to be tested). 1.2.1 The nominal ranges of collector current over which the three test circuits are intended to be used are as follows: 1.2.1.1 Circuit 1, less than 100 [mu]A, 1.2.1.2 Circuit 2, from 100 [mu]A to 100 mA, and 1.2.1.3 Circuit 3, greater than 100 mA. 1.3 This test method incorporates tests to determine if the power dissipated in the transistor is low enough that the temperature of the junction is approximately the same as the ambient temperature. 1.4 The values stated in International System of Units (SI) are to be regarded as standard. No other units of measurement are included in this standard. 1.5 This standard does not purport to address the safety problems, if any, associated with its use. It is the responsibility of whoever uses this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
