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GOSSEN mA / mV - METER » MAVOMETER «
MILLI-AMP / -VOLT-METER » MAVOMETER « GOSSEN / Germany (1930)
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Dimension ( W-D-H ) 85 mm x 125 mm x 40 mm / 3_3/8" x 5" x 1_5/8"
Class 1 ; 2 mA / 100 mV ( Ri = 50 Ω ) w/o Shunt / Ser.Resist.
R E M A R K S: SN = 47170
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The rubber feet had to be remade out of an old leather belt. The
» MAVOMETER « came in a wooden case. Originally the instrument
get connected by pushing the WHITE BUTTON (w. Pre-TEST-Feature ).
For CONTINUOUS MEASUREMENTS I have blocked it inside by a wedge.
EXPERIMENT: SHUNT = 32 Ω ==>> 5 mA Range ( on "50" Scale )
SER.R. = 3.75 kΩ ==>> 7.5 V Range ( on "75" Scale )
This f a m o u s bakelite precision instrument was a forerunner
of Multi-Meters: A set of SHUNTS & SER.RES. was available ...
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... like this in a BOX (... BUT NOT IN OUR MUSEUM !)
HOW A "MOVING-COIL-METER" (= "DrehSpulMeter") WORKS:
A to measure current I in the coil produces a magnetic field ---
This field interfers with the field B of the permanent magnet and
generates a force F, moving the pointer ( α ) proportional to the
current I.