Large volume of high and low temperature test chamber can fully meet the test standards, but the heating and cooling chamber may require the use of forced air circulation, in this case, the test samples shall be placed in the test chamber with temperature, checks on the surface of the test sample all the representative points inside temperature is not subject to forced air circulation over the impact of the test sample if the surface temperature at any point, not because of the high and low temperature test chamber with forced air circulation by 5 degrees or more, as in the non-forced test chamber air circulation test, as the cooling effect of the forced air circulation can be considered quite small, negligible, if the high temperature chamber volume is small, does not meet the test requirements, or the standard of the surface temperature difference between the measured more than 5 degrees, it is desirable to explore outside the test chamber test:
     Place the test sample placed in the first chamber of the test chamber to change, I am afraid I applied the test temperature for a given load condition to get together, some on the surface of the test sample measured representative point temperature to give the calculated surface temperature under specified test conditions reference point, the ambient temperature of the surface of the small temperature difference between the temperature, as long as the ambient temperature changes can be assumed that the temperature difference at various hours of the ambient temperature is the same.
     Different environmental temperature, the high and low temperature test sample surface the same relationship between temperature, if known, when a surface temperature of the ambient temperature, the ambient temperature can be calculated by any of the surface temperature, so that when the time of the test sample at room temperature, when the surface temperature is known, we can extend the specified test conditions to calculate the surface temperature of the range.
     When adopted two standard test method, the test sample should learn more about the situation (such as temperature distribution, thermal limit point, etc.), because of this choice is mainly a training determine the problem, it is recommended that priority be used without forced air circulation test methods for exploratory trials, it may need to verify the performance of high and low temperature in order to carry out a series of similar tests (eg tests similar components), while the other cases (eg for different products), in every trial chamber before they need to be evaluated.