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TRANSISTORIZED
R-L-C   WHEATSTONE  BRIDGE


WHEATSTONE BRIDGE for Resistances, Inductivities & Capacities     (1972)
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VEB MESSTECHNIK MELLENBACH / THURINGIA  ( former GDR / Eastern Germany )

Dimension   ( W-D-H )   115 mm x 210 mm x 78 mm  /  4_1/2" x 8_1/8" x 3"

The INSTRUCTION is on its back side ...



Have a Look INSIDE ...



A stamp  » 30.Aug.1972 «  is readable



R E M A R K S :         See in "FAQs" a picture of this BATTERY TYPE ...
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The  named  » ECT-TGL 7487 «  Batteries  are   3 x 1.5 Volt  =  4.5 Volt
made  of   H A L F S   of  3 Volt Batteries,  eg.  » VARTA DUPLEX 3010 «

RESISTANCES  can be measured either by using the Zero-Instrument or with
the build-in  transistorized  Square-Generator ( 50 mV[pp] / 1 kHz ) and
headphones. INDUCTIVITIES & CAPACITIES have to be use the tone-generator
with  a  KNOWN (!) INDUCTIVITY ( LN )  or  a  KNOWN (!) CAPACITY ( CN ).
See INSTRUCTION above:   LX = 1/3 * LN * SCALE  ;    CX = 3 * CN * SCALE 

My Set of  CALIBRATION  CAPACITORS ...



REMARKS  to   R E S T O R A T I O N :
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The instrument came  with cut wires inside  and the cracked  "RED LEVER"
(= holding the central switch axle ).  To have access  to the  soldering
side of the print-board, not only the board-screws  also the axle has to
be freed inside by removing its nuts & clips. After electrical repairing
the damaged RED LEVER got a new HOME-MADE CENTER-PART out of brass-sheet
glued with the LEVER-ENDS ( see above ). 

                About the Wheatstone Bridge Therory ...

                Back to the PAIR Site ...
impressum:
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© C.HAMANN      http://public.beuth-hochschule.de/~hamann       03/31/13