Programmable DC Electronic Load Applications

Programmable DC electronic loads are useful for a variety of test and measurement applications including battery testing and characterization as well as testing power supplies and solar panels. We will discuss these three types of applications in this article.

A programmable DC electronic load is ideally suited for testing any battery, especially rechargeable lead-acid, NiMH, NiCad, and Li-ion battery packs. The ability to set a minimum voltage level enables unsupervised discharge of the battery pack under test. The type of battery you are testing will determine the parameters you will program into the electronic load. These parameters include end of discharge voltage and discharge current. Some higher-end electronic loads feature an automatic battery testing feature that automates battery testing, but you can use any DC electronic load for this operation.

DC power supply testing is the most common use for an electronic load. Voltage and current output values can be verified as well as current limit and constant current operation. You can easily measure power and regulation with an electronic load. If the load has a computer interface, you can log temperature and time variance information for future reference or for documentation requirements.

As solar power becomes more affordable and popular, DC electronic loads have become an indispensable tool for characterizing and testing photovoltaic solar panels. For this type of test the load should be capable of constant voltage operation, which enables you to step through the output voltage value while measuring the resultant output current. Constant voltage operation provides you with a current versus voltage (I-V) curve that shows all of the solar panel’s characteristics, including the maximum power point at which the solar panel is operating most efficiently.

Although we have outlined several common uses for a programmable DC electronic load, this list is by no means exhaustive. Transient load testing and power supply recovery are also possible with some of the more complex electronic loads available at Circuit Specialists.


George Leger has a Masters in Electrical Engineering from Stanford University, worked in private industry pioneering surface-mount technology and in government research labs for twenty years, published several papers on surface-mount technology, co-authored papers published in national symposiums on accelerator technology, was past president of SMTA and an adjunct professor at the community college level, holds a patent, and is a certified microchip design partner, serving as a consultant to many companies developing electronic circuits.

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