[sdiy] (ot) diy lcr bridge help and ca3020

[Peter Blackett]

Dear List,
I've recently bought secondhand from a ham radio swapmeet( I think that
is the correct term ?) a homebrew lcr bridge possibly made by G3ZZX.
I just wondered if anyone had any pointers as to how to understand using
it? it could be a published design, but it doesn't seem to relate to any
of the articles I found online at
http://www.vintageradio.me.uk/radconnav/misc.circuits/
but there are some usefull articles there.
the main question I have is that I can work out how the range switch and
course / fine controls work,but there are two more controls that I think
are 1. for meter sensitivity and 2. for q factor.I'm not familiar with
how the q factor would be used .
I am going to copy out some of the schematics so I can understand how it
works,but any advice would be welcome.it uses a ca3020 ic in the meter
drive circuit, which I've got to read the data sheet to know why it was
choosen.
regards Peter