Standard No .: GB2423.22 Basic environmental test procedures for electrical and electronic products Test N: Temperature change test method, a kind of routine test standard for high and low temperature test chambers, suitable for determining the effect of one or more consecutive temperature changes on test samples (Note : Can not be used to assess the impact caused by high temperature or low temperature only. For this effect, the high temperature or low temperature test method should be used. The main parameters that affect the temperature change test are:
1. High-temperature and low-temperature temperature values ​​in the temperature change range;
2. The retention time of the test sample at high temperature and low temperature;
3. The rate of temperature change from low temperature to high temperature or high temperature to low temperature;
4. Number of conditional test cycles;
5. The total heat absorbed or released by the test sample.
Test Na: stipulates the rapid temperature change test for changing drought
Purpose of the test: To confirm the ability of components, equipment and other products to withstand rapid changes in ambient temperature.
Brief description of the test: Expose the test sample alternately to low-temperature and high-temperature air (or suitable inert gas) to subject it to rapid temperature changes.
Description of the test equipment: there should be one low temperature box and one high temperature box, and the two boxes should be placed in a position that allows the test samples to be transferred from one box to another box within the specified time. The conversion method can be manual or automatic (Note: If the manual method is used, the high and low temperature test box is used. If the automatic type is used, the two box type cold and hot shock test box will be used. The absolute humidity of the air should exceed 20G per cubic meter, the temperature of the high-temperature box wall should not exceed 3% of the temperature specified in the test, and the temperature of the low-temperature box wall should not exceed 8% of the test. This requirement applies to the entire inner wall of the test box There should be no direct radiation between the test sample and any thermal heating and cooling elements that do not meet the above requirements.
The volume and air speed of the test box should meet the time for the temperature of the air in the box to return to the specified tolerance range after the test sample is placed, not exceeding 10% of the test exposure time. The speed should not be less than 2mS.
Mounting brackets and supports for test samples: Unless otherwise specified in the relevant standards, the thermal conductivity of the mounting brackets or supports should be low, so that the test samples are actually insulated. The air between each test sample and between the test sample and the box wall can circulate freely.
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