INTRODUCTION
What is a test load and why do I need to use one? How and
when should I use one, and how do I know it’s working?
These are questions our technical support staff are asked
regularly, along with how to set up a test load and which load
is best for each Wavelength product series. This Application
Note will cover that information, as well as what equipment
you need, when to use Constant Current or Constant Power
modes, and how to prepare your equipment for the actual
load. For the purposes of this paper, we will address using
test loads with only temperature controllers and laser diode
drivers.
A test load is a tool for testing a device or system and
measuring a response without using the application load
and, ideally, the test load should closely mimic the eventual
load. Using a test load is a good way to get familiar with a
controller, test how it works, and make sure it operates as
expected before the fi nal set up. For example, laser diodes
can be expensive and are usually not readily available, so
destroying one during set up can be both costly and time
consuming. To avoid this hazard, the system can be set up
with a test load and tried before attaching the laser diode.
A test load can also help show, through monitoring, what
happens when limits are exceeded. Additionally, if you are
having a problem while using a system, a test load can help
troubleshoot any problems.