Answers to Electronic Load Questions 
Executive Engineering at Exec-Eng.Com



  • Can I increase the power of the load?
    No! But you can add more electronic loads in parallel.
    1 = 300 Watts
    2 = 600 Watts
    3 = 900 Watts
    4 = 1200 Watts
    5 = 1500 Watts
    If you had 4 loads in parallel you would be able to dissipate 1200 Watts of power.
  • How much power can I dissipate?
    Each electronic load can dissipate 300 watts if it is mounted on the correct heat sink. To give you an idea of what that is, hear is an example.
    Example: 1
    Room temp 25C / 300Watts to dissipate. You would need EE301xx or EE151xx series load.

    Wakefield 392 / 860 series heat sink 3.0 inches long & side & bottom covers, with a 40CFM fan.
    Example: 2
    Room temp 50C / 300Watts to dissipate. You would need EE300xx or EE400xx series load.
    Wakefield 392 / 860 series heat sink 3.0 inches long & side & bottom covers, with a 100CFM fan.
    Note: always remember to check the temperature of the heat sink.
    The lower the base plate temperature the longer the electronic load will last.
  • How many electronic loads can I put on one high power heat sink?
    In real terms, if you are using a 15" or 16" heat sink 3 electronic loads, with about 1.25" space between them. If you are going to run them at full power @ 50C you will need at least a 90CMF fan and all the side panels to force the air down the sides of the heat sink.

    Note: If you are going to use air filters on your load this will decrease the air flow some what.
  • Why do I need a heat sink that is so large?
    The problem is getting the heat away from the power devices. Large heat sinks provide a large area, or volume, for air to flow past. This allows the power devices to get the heat away. This is why most electronic load manufacturers derate their loads above 25 degs C.
  • What is the difference between an Extrusion Heat Sink and a Plenum Heat Sink?
    Usually the extrusion is made from one solid piece of aluminum where as the plenum types are made of many fins that are bonded to a single aluminum base. The extrusions, in general, do not have as large a cooling capacity as the plenums do
    for the same volume of space.
  • To save space, can I use a water cooled heat sink?
    Yes. Sometimes this is referred to as a cold plate.
  • Can I use a copper heatsink?
    Yes. Sometimes this is better than an aluminum heat sink, remember that copper conducts heat faster than aluminum.
  • Is it ok to use microprocessor heat sinks on the electronic Loads because they are made of copper and have a high fan rate?
    No! No! NO! Processor heat sinks do not have the ability to conduct heat away fast enough for the electronic loads. The area of the heat conduction is to small and the fans on the processors were not meant to dissipate this volume of heat. Most processor heat sinks are meant to work in the 50-60 watt range.
  • Can I use a heat sink with a thin conduction valley?
    NO!. The conduction valley ( solid or mounting ) where the fins attach should be a thick area. This area helps conduct heat in all directions and help in heat transfer to the fins of the heat sink, this is how the heat is removed.
  • Do I need to add thermal compound to the bottom of the electronic load?
    Yes! In most cases it is a very good idea to add thermal compound to the bottom of the load to help in heat conduction.



Executive Engineering Home

Terminology of Electronic Loads

Current Ctrl of Electronic Loads

Powering the Electronic Loads

Heat Sinks for Loads

Using DtoA's & AtoD's

Selecting an Electronic Load




Increase Load Power

Power Dissipation 

Loads on a Heat Sink

Large Heat Sinks

Difference in Heat Sinks

Space saving Heat Sinks

Copper Heat Sinks

Heat Sinks NOT to use!

Thin Heat Sinks

Thermal Compound