## tikz circuits library causing pgfkeys error

I'm trying to use tikz circuit library in a document I'm typing up. But I'm getting the following error:

/usr/share/texmf/tex/generic/pgf/frontendlayer/tikz/libraries/circuits/tikzlibr
arycircuits.code.tex:103: Package pgfkeys Error: I do not know the key '/tikz/p
os/.belongs to family' and I am going to ignore it. Perhaps you misspelled it.

Any ideas what may be causing this? Thanks.