This is a Marconi TF868/1
used for measuring Resistance, Capacitance and Inductance
Somewhat larger and more consuming
of power than the latest hand held LCD multimeters but in the
50's, 60's, 70's and even much of the 80's you didn't have a
lot of options. It was either the trusty AVO, or one of these
if you wanted to look the part. It came from the same place as
Ranges were quite decent and
like other Marconi instruments the design is well thought out;
& 100uF with tan delta
& 100H with Q
The principle of the bridge
requires the meter to be dipped using appropriate delta or Q
settings with capacitors or coils.
Measurements of resistance are
made at DC whilst C and L are measured at either 1KHz or 10KHz
and measurements to 3 significant figures are readily made.
Not that easy to use otherwise
why would they written all the instructions on the top!