Measuring range switch for the automatic setting of measuring ranges

摘要

Conventional measuring range switches use controllable relays which switch in voltage divider resistors determining the measuring range for automatically switching over the measuring range. It is the object of the invention to create a measuring range switch which can be largely accommodated in an integrated circuit. In each case one of the divider voltages picked up across the voltage divider resistors (R21, R23) is supplied to the base of a switching transistor (Q12, Q18) operating as emitter follower. All emitters of these switching transistors (Q12, Q18) are connected to a common output resistor. At the base of each switching transistor (Q12, Q18), a control transistor (Q13, Q19) is connected by which, in dependence on signals of a control circuit, which are present at its input (11, 14), only the switching transistor (Q12, Q18) which is allocated to the in each case predetermined measuring range is not connected to inhibiting potential. The invention can be used in instrumentation in multimeters and oscilloscopes. <IMAGE>