Quick free product testing for Environmental and ESD issues

Here we present ways do free product testing quickly on the bench. Such environmental and ESD tests enable us to identify and correct problems right in the prototype stage.

You must adequately test the product for all relevant conditions before shipping it out. Products fail in unexpected ways and it is important that they fail in the lab, before they fail in the field. The cost of fixing a product in the field is many times the cost of fixing it in the lab.

Depending on the usage of your product, there may be preexisting standards, like MIL standards or IEC standards, for testing such products. Even if you are not legally required to test to the standard, it is a good idea to go through the standard, identify relevant tests and perform these tests. These standards were defined by experts after industry input, and often contain a lot of good sense.

It is also important that testing be performed early in the product lifecycle. It is easier to fix an issue early in the development cycle when design can still be modified, than later when the design is fixed.

For these reasons it is important that we have ways to test the product quickly and cheaply. Being able to replicate test lab conditions on the bench is easy.

One should test for

• Temperature testing: Test at temperature extremes - at high temperature with system at full capacity, so that components are operating at full capacity. If you have a power supply with variable input voltage, test at the highest input voltage so that you are testing at maximum heat generation conditions.
• EMI: An RF spectrum analyzer capable of sweeping the frequencies of interest is needed. These have become cheaper over the years. Please note that in the absence of a shielded RF chamber and antennas with proper gains, any readings would be indicative but not definitive. You actually have to test for this, one cannot take the radiated and conducted EMI values of the components used in the system and simply add them together. The components and cables of the system interact in unique ways to create their own EMI pattern. In general keep cable lengths short, use proper shielding of cables and components and if all else fails use common mode chokes on cables.
• Shock and vibration: If your equipment is to be subject to shock and vibration, it is important to test for it. You can make a shock and vibration jig in the lab. We once literally had a piece of customer supplied equipment disassemble itself, as the person doing its assembly had forgotten to put the loctite on and/or use proper lock nuts, and the screws worked their way out.
• ESD testing: It is important to test for Electrostatic discharge. An effective way to do so in the lab is detailed below.

If you require a formal certification you will have to get it certified by formal testing laboratory. Environmental testing laboratories will give you a quote and a schedule for getting such testing done. Depending on the testing that you want to perform these may turn out to be expensive. You want to be very sure that you will not have any major problems when you show up at the lab with your product and its test harness.

Here we present a few ways that we have found for testing the product on the bench. This way we avoid expensive and time consuming trips to the laboratory.