A note about calibration of test equipment (many listings state calibrated tube testers are used in their testing). The test equipment must be on a calibration schedule with periodic re-calibration. A calibration certificate means that at the time of the calibration the test equipment was calibrated to a given set of specifications. First, one must understand what those set of specifications are to make sure that the critical performance parameters were included. Once the test equipment has been calibrated, often by a third party, it is shipped/moved to other lab bench/etc. At any time after calibration, the test equipment could incur damage/misuse/mishandling/etc. - and it is not always visible or readily detectable. When the test equipment is re-calibrated, if it is found to be within specifications, then there is a reasonably high assurance that measurements made between the calibrations are valid. If, at re-calibration, the test equipment is found not to be within specifications, then those out-of-specification parameters need to be analyzed to determine if previous measurements may not be valid. Speaking from 45-years as a degreed Electrical Engineer who is still quite active in the field.
I will mail within one business day of receiving cleared payment.
Please ask questions before purchasing.