I had to interview several people over years.
the work was/is industrial automation (design, PLCs, robots, motion control, vision, safety, PC programming, networking etc.). yes there is a lot to learn and this takes time. most candidates are inexperienced and looking for a chance to get in and learn on the job - and that is fine. little bit of guidance and working with someone else on few projects takes you far. before interview many are unaware of existence of something called 'electrical code', have never dealt with industrial robot, safety circuits, networking or even worked with plc. things that I value are dependability, ability and willingness to learn and common sense. i focus on key things but also ask whatever may be on a resume - if someone puts something there, they must want me to read (and ask) about it.
i don't care about what candidate brings with him in a suitcase (piles of drawings, electronic files etc), i need to know what is in their heads - so i give them little job-related problems, usually quite simple and practice oriented (troubleshooting circuit, fixing piece of code, sizing something etc.). few freak out right away, expecting that because they have some piece of paper to present and assure their educational background, they are entitled to a job without any question.
no-nonsence questions include just calculating power, voltage drop, interfacing (PNP/NPN), troubleshooting (use of multimeter) and evaluating code sample. rest are questions about things in his/her resume. i don't bother with "would you like to work with us" etc. - i know why you are here.
two amazing but true cases:
one candidate with experience of 20+ years of designing circuits and troubleshooting at PCBs level. although he had no other relevant experience he wanted the job (and we could use some help). turns out the only things we could talk about is his alleged work experience and to my surprise even that didn't go well. according to his claims and resume he used hundreds of components but mostly worked with some 20-30 very common ICs that he listed there. his problem:
- he didn't expect that i would know any of them (ICs)
- he didn't know any of them (he claimed that CMOS 4000 was family of operational amplifiers and comparators, 555 was voltage regulator and TDA2030 was TTL chip, not ONE of his answers was correct)
- he didn't pass the no-nonsense part (couldn't solve voltage drop and sizing series resistor in a DC circuit; couldn't use any of our meters to measure DC voltage or continuity claiming that all of them were strange: two Flukes, one GreenLee DM210, one el-cheapo MasterCraft and the old analog Simpson 260).
If this was someone fresh from school, I would still expect him to solve and troubleshoot circuit but wouldn't bother asking about ICs even if they were on his resume. but when someone tells this has been his bread for many years and then comes with this BS, that just doesn't cut it...
an hour later my boss comes in and goes straight to my desk: "why didn't you keep the guy, he worked for two good companies...".
me "i don't think they'd want him, but if YOU hire him, i'll have no objections..."
he wasn't hired.
one other guy worked for competitor for several years then got laid off so came to us looking for job. he claimed that the only thing he was ever asked to do was plc programming and therefore he could not recognize any sensors, disconnects, transformers etc, couldn't troubleshoot or use multimeter etc. (sigh).
ok mr. programmer, you asked for it:
"...what is bit?"
" 8 byte!"
" and what is byte"
" 64 words"
" two words: good bye!"