Ohmmeter with high and low ranges - uses measurement resistance changeover, divider, and high range potential divider

摘要

The resistance measurement device enables resistances in both low and high resistance ranges, i.e. approximately 0.1 milliohms to 200 kilohms and 50 kilohms to approx. 10 power 14 ohms, to be measured. It provides a directly proportional indication in both ranges. For the lower range a low resistance measurement voltage source is applied to a test resistance and a low resistance measurement resistor in series. The voltage drop across the resistors are input to a quotient circuit. For the higher range a high resistance measurement source is applied to the test resistance and a high resistance reference resistor in series and to a potential divider in parallel with them. The potential divider and the reference resistor provide the divider inputs. A range change switch connects either the low or high resistance measurement resistor in circuit.