Electrical multi-position measuring device

An electrical bridge circuit arrangement for multi-position measuring, comprising supply voltage means (1, 2), measuring bridge branches, and an auxiliary half bridge (R.sub.3, R.sub.4), individual measuring means in a respective measuring bridge branch of said measuring bridge branches, said individual measuring means including measuring resistances (M.sub.1 ;

• M.sub.2 ;
• M.sub.3) each arranged in a respective measuring bridge branch, and a standard resistance (E) arranged in common to all measuring substances, first switching means (S.sub.12, . . . S.sub.E3) for selectively connecting said individual measuring resistances to said supply voltage means (1, 2), a first voltage tap (Ta, Tb, Tc) provided between measuring resistance and said supply voltage means, first switching means (S.sub.12, . . . ) between the respective measuring resistance (M.sub.1 ;
• M.sub.2 ;
• M.sub.3) and said voltage supply means, a second voltage tap (Td) between said standard resistance (E) and a respective supply voltage conductor (L.sub.E3), closed loop control means operatively connected to said first and second voltage taps (Ta, Tb, Tc, and Td), said closed loop control means comprising a voltage summing circuit (9, 11), reference voltage supply means (12) connected to one input of said voltage summing circuit for supplying a reference voltage value (U.sub.Ref.) to said one input of said voltage summing circuit, said voltage summing circuit providing a voltage sum to said supply voltage means (1, 2) for readjustment of said supply voltage means (1, 2), said bridge circuit arrangement further comprising third voltage taps (T.sub.1, T.sub.2, T.sub.3) between said measuring resistances (M.sub.1, M.sub.2, and M.sub.3) and respective conductors (L.sub.1, L.sub.2, and L.sub.3) connecting said measuring resistances (M.sub.1, M.sub.2, M.sub.3) to said standard resistance (E), and a fourth voltage tap (T.sub.4) between said standard resistance (E) and a connecting conductor (L.sub.E) connecting said measuring resistances (M.sub.1, M.sub.2, M.sub.3) to said standard resistance (E), voltage follower means (7, 8) connected to said third and fourth voltage taps (T.sub.1, T.sub.2, T.sub.3, and T.sub.4) for measuring a voltage drop (.DELTA.U.sub.1) appearing across outputs of said follower means, means connecting said voltage drop (.DELTA.U.sub.1) to other input means of said voltage summing circuit (9, 11), whereby one half of said voltage drop (.DELTA.U.sub.1) is supplied to the respective measuring bridge branch of the bridge circuit arrangement and the other half of said voltage drop (.DELTA.U.sub.1) is supplied to the standard resistance in said auxiliary half bridge branch, said voltage summing circuit (9, 11) being connected between said voltage follower means (7,8) and said reference voltage supply means for increasing the bridge supply voltage by said voltage drop (.DELTA.U.sub.1).