I take a look at an oscillation problem with the oscilloscope and test to see if the load resistor acts as a sense / feedback for the op-amp to regulate the current.

Link to Kibi’s “Dave Jones’ dummy load with added features” :
http://mjlorton.com/forum/index.php?t…

Dave Jones / EEVblog video:
http://www.youtube.com/watch?v=8xX2SV…

WHAT IS AN OP-AMP?:
http://talkingelectronics.com/project…

My components:

* Infineon MOSFET N-channel 200V 13.5A TO-220 – BUZ31L H
* Vishay 534 Series Pot with 6.34mm shaft, 50K
* 2 x 10 k Ohm resistors
* Arcol HS50 Al house wirewound high power resistor,1R (1 ohm) 50W – HS50 1R J
* National Semiconductor Quad op amp,LM324N 1MHz DIP14
* UNI-T / Trend UT81B Scopemeter / oscilloscope.

* How does an N Channel logic level MOSFET work – gate voltage, variable resistance, heat dissipation.
* How does a LM324N Op Amp work – voltage follower, comparator, rail to rail, head room, feedback loop.
* What is the heat / power dissipation from a variable resistor?