Single Cell Battery Meter Amplifier

A meter amplifier can be designed using LM10 integrated circuit (IC). The accuracy of full-scale sensitivity is good for over 15°C to 155°C at 10mV and 100nA.  Here is the schematic diagram of the circuit:

R5 is used to correct the offset voltage error, while R4 is  used to balance the bias current. The zero calibration uses the reference voltage of the IC, so it will be independent of battery voltage level, avoiding frequent adjustment as the battery voltage drains out. The low current consumption  , below 0.5 mA, make the  circuit keeps running for 3-6  month with AA cell battery, or over one year with D cell battery. [Circuit’s schematic diagram source: National Semiconductor Application Note]