Mobile Battery & digital voltmeter

Discussion in 'General Electronics Chat' started by aamirali, Aug 10, 2012.

  1. aamirali

    Thread Starter Member

    Feb 2, 2012
    415
    1
    Hi,

    1. There are three terminals in mobile li-ion battery. Two are +ve & -ve. What's the third one.

    2. I want to make digital voltmeter using MCU.

    How do they measure voltage by using float voltmeter. +ve lead I can connect to input of adc pin o MCU. How to make -ve lead of it. Will it ground of MCU. If yes, can I measure flaot voltages.

    Usually specs in DMM are like 10M while measuring voltage. How this thing can be implemented in my ckt. Should I add separte 10M resistor, or internal imepdence of pin is high.

    How resistance are measured in DMM. How does it vary with different ranges like 100, 10K,1M
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,754
    760
    How can u make a DMM when u dunno the theory behind it.

    Google is ur friend. Try it for a change
     
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