For hardware types ask them to draw a full wave bridge rectifier.
At one place a recent-grad systems engineer was hired to do board repair. When asked to identify components, he said "I think those are resistors because they have colours on them."
He lasted about a week.
For a real engineer, ask how many soldering irons they own. We tend to upgrade from a simple one when we can afford it, but can't get rid of the old one because it may be useful for something. Then there are high power units for big jobs.
Have a small device on the table that isn't screwed together. Se how much time is spent looking inside, how long is spent operating it.
Engineers are more interested in what us inside something than what it does.
This assumes the device is a well-known gadget, not a functioning TriCorder!
As we unveil EE Times’ 2015 Silicon 60 list, journalist & Silicon 60 researcher Peter Clarke hosts a conversation on startups in the electronics industry. Panelists Dan Armbrust (investment firm Silicon Catalyst), Andrew Kau (venture capital firm Walden International), and Stan Boland (successful serial entrepreneur, former CEO of Neul, Icera) join in the live debate.