MEASURING RANGE AUTOMATIC SELECTING CIR- CUIT OF DIGITAL MULTIMETER

摘要

PURPOSE: To reduce loss time at selection and to reduce measurement time by, after a measured voltage at an attenuation part is compared to a reference voltage of a parallel A/D converter, selecting a measurement range with a digital signal outputted through an encoder. CONSTITUTION: A measured voltage Vin is attenuated at an attenuation part 1, and then outputted as an output voltage Vx . The voltage Vx is inputted in a 3 bit parallel A/D converter 10 for measurement range selection, and at the same time, inputted in an A/D converter 2. The voltage Vx which has been inputted in the converter 10 is, after compared with an internal comparator, outputted as a 3 bit digital signal, and the attenuation part 1 is controlled by selection part of a control logic and measurement range selection part 4, and then it is outputted as the output voltage Vx belonging to a measurement range. Thus, a lass time at selecting an automatic range is reduced, so that a measurement time is shortened.