checking supply voltages on ic's

Discussion in 'General Electronics Chat' started by dale1899, Dec 13, 2013.

  1. dale1899

    Thread Starter New Member

    Dec 13, 2013
    I need some help on measuring supply voltage to ic's.
    I obtain the data sheets and know which pins are what.
    Do i measure across the ic pin4 (-) to pin8 (+)
    or ground to pin8 (+).
  2. tshuck

    Well-Known Member

    Oct 18, 2012
    Which part is this in reference to? The supply pins are not always the same...

    Measure ground versus the supply pins...
  3. BillB3857

    Senior Member

    Feb 28, 2009
    If I'm having problems, I usually measure right at the IC pins (both+ and -). I've seen problems where a broken PC trace removed ground from the IC.
  4. dale1899

    Thread Starter New Member

    Dec 13, 2013
    Thank you for the responses.
    I thought it would not matter which way, but billb3857 makes sense.

    There are about 20 IC's on this metal detector unit.
    All require 10v except 2 (7v and 5 v) according to data sheets
    All read 9.9volts, except for 6 IC's
    These 6 if done across IC, read 2.2volts
    if done from ground to (+) pin, read 7.78volts

    And oddly, if these 6 are measured from ground to the (-) pin
    read 7.78volts.
    All the rest measure- 0.0 volt

    So, it looks like I have some tracing to do