[TriEmbed] Shane's constant current load PCBs

[Pete Soper]

This is about the adjustable, constant current load PCBs that Shane 
Trent made available starting a year ago in conjunction with this blog 
post <http://fettricks.blogspot.com/2014_06_01_archive.html>.

I built one of these and tested it to confirm it will provide an easily 
adjustable, constant current load from a small fraction of an amp up to 
a few amps,  depending on the power involved. As near as I can figure 
the transistor doing the work in combination with the heat sink it's 
bolted to can deal with 18 watts before the transistor junction 
temperature limit is exceeded.

I'm almost done building a second one that could be a "TriEmbed Club 
Loaner" for folks that would like to experiment with it.

Some of these PCBs were claimed at the last meeting but there is at 
least one more available for anybody that would like it.

My builds use a precision five watt resistor in place of the 10 little 
through hole ones, and I've got proper screw terminal blocks for the 
load connection. It would be great to get input on a decent connector 
for the current sense. Jamming multimeter probes into these holes is 
only interesting for a short time.

It should be relatively straight forward to make this load programmable 
by insinuating a control voltage into the op amp circuit to functionally 
replace the adjustment pots. If somebody would like to pursue this I'm 
sure we'd be relaxed about nearly any level of hacking of the loaner in 
return for design details.

-Pete




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