The purpose of this application note is to describe the operation and potential pitfalls of a 10V resolution (VREF = 100mV) 4 1/2 digit autoranging scheme using the ICL7103A/ICL8052A pair. Two auto-ranging circuits are included within the text. Each is discussed in terms of its advantages and disadvantages.
This application note describes a technique for auto-ranging a battery operated DVM suitable for panel meter applications. Also, circuit ideas will be presented for conductance and resistance measurement, 9V battery and 5V supply operations, and current measurement.
Battery level voltage measurement is best done with a dummy load. This circuit has four LEDs to show the charge left. It is important to avoid overcharge or deep discharge of rechargeable batteries. Never try recharging normal batteries. Using rechargeable batteries are good for the environment.