Hi. I'm joining this forum to ask about some equipment I need. At the community college where I teach, we do a lab in freshman physics where students measure the input to and output from a transformer. My AC sources are reaching the end of their lives, so I'm looking for replacements. As far as I can tell, what I need is 110 V at 60 Hz input 0 to 15 or 20 V output in at least four steps (e.g., 4 V, 8 V, 12 V, 16 V) Current up to at least 1.5 A Reasonably sinusoidal output, not clipped or chopped, at all voltages Output easily connected to banana plugs or alligator clips Price no more than a few hundred U.S. dollars What I'd like, more or less in decreasing order of importance, is Output voltage limited or limitable to something definitely less than 100 V Good quality--steady output voltage, long life even if bumped, easy fine adjustment, anything else that comes to mind Continuously adjustable output voltage DC operation with an on-off switch (for another part of the lab) Accurate digital meters of output V and I Can anyone suggest anything? Thanks in advance.