automatic range switch

10 It is often convenient to utilise an automatic range switch (autoranger) when measuring with digital meters. Unlike the forgetful human, an autoranger ensures that the range is altered before any damage can be done to the actual meter. It detects whether the measured parameter (be 1 automatic range switch T1 R12 0 Ell Ce P1 T2 dr 1.6 BC 547 4 n7 O 0 16 BC 557 100k R3 R4 R5 5 Ve • 0e to IC3 O T (;) 80603 - 1 106 ,c, it voltage, current, resistance etc.) is "out of limits" and increases or decreases the range accordingly. The automatic range switch shown here operates on exactly the same principle. A maximum of ten decades can be switched with it. The logic signals to control the circuit are derived from the conditions "over- flow" and "first figure = zero". In the case of the Universal Digital Meter (Elektor, January 1979) these will be the BCD codes 1011 and 0000 respectively and are determined the moment the first digit is multiplexed to the display. For this reason the R71 ...