Paul Hovnanian P.E. wrote:
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How is it reading in the Volts ranges? These things have only one A/D
converter and display. Everything else is input conditioning, range
selection and (for ohms) a current source.

** Hand held DMMs do not use current sources for resistance measurement.

Rather, they read the *ratio* of two voltages, one across the unknown part and the other across an accurate reference resistor.
This is both simpler & far more accurate.

Also, they do not use normal A-D converters.

An analogue technique called " dual slope integration" converts the DC input voltage to a precise time interval.
This interval is used to pass clock cycles from a time base which counted and displayed in decimal form.

The "digital " bit is only the display.


...... Phil