Resistive loads are easy on a DC power supply. When you turn off the power, the current quickly drops to zero and no damage is done.
To maintain signal integrity in an automatic test system requires:
Over the past 10-20 years, counterfeit electronic components have become a serious problem. Counterfeit components are parts that have somehow been misrepresented as to their origins or quality. Because counterfeit parts are often of lower quality than what are called “franchise” parts, they may represent a hazard if used in critical systems such as automobiles, aircraft of any kind, military equipment, or space vehicles.
Designing equipment to be operated onboard Navy vessels is not like designing a consumer product that plugs into a three-prong wall socket. That being said, it’s important to know the characteristics of the on-board power source and test to make sure that equipment can reliably use that power.
Testing AC power sources, such as uninterruptible power supplies, can be a real challenge. These products are often tested with resistive load banks, but this approach does not simulate real-world conditions such as switching DC/AC converters found in many AC powered products.
When performing functional tests, keeping test times as short as possible is often a critical requirement. Time is money, after all. One way to reduce test times is to reduce the latency in setting up signal switch paths, stimulus devices, and measurements. These can all have a significant impact on the overall time it takes to complete a full functional test of a particular DUT.
Calibration is not an option. While today's instruments are more accurate and drift less than previous generations, you still need to periodically check and calibrate your equipment. The way you do this, however, is changing.
In the past, manufacturers would recommend calibration intervals. A digital multimeter manufacturer might, for example, recommend that you calibrate the instrument once a year. When that year was up, you sent the DMM to your company's cal lab or to a third party.
That paradigm is changing. The current trend in metrology is not to blindly follow a manufacturer’s stated calibration interval, but to determine your own interval based on how much each instrument drifts over time and how much risk you're willing to take.
Topics: AC Power Sources, Compliance Testing, DC Power-Supplies, Electronic Loads, Uninterruptible Power Supplies, Programmable Power, Programmable Power Solutions, Solar Testing, total cost of ownership
Power systems operate at frequencies of 50 or 60Hz, but some devices, including personal computers, printers, and some industrial equipment, present a non-linear load and create currents and voltages with frequencies at harmonic frequencies. These harmonics get fed back into the power system and can cause other devices connected to the power source to malfunction. There are several standards that specify the level of harmonics that a particular device can produce.