I need to find something like this but that is automatable, over I2C or GPIB or something.
Is there a name for this? I am having problems finding something. Worst case I can buy this and hook up a motor to it, but I imagine a cheap packaged solution already exists, I just don't know the name for it.
Looking for these specs: 7Vrms (so ~20W at the low end of 3ohm, <1W above 50ohm) 3ohm-100ohm in ~20 log spaced steps Automatable
A decade box could also work if it were automatable. They seem to be very expensive ($6k) for both automatable and specced for power.
The specific application is for loading a sigma delta (Class D) op amp (an audio amplifier). The output is differential and switching, a 1kHz AC sine wave is the resulting waveform after low pass filtering. A constant DC current sink will not fit the bill unfortunately. Open to other solutions though!