Resistor showing incorrect value in circuit

Discussion in 'General Electronics Chat' started by rokz_2005, Mar 30, 2015.

  1. rokz_2005

    Thread Starter Member

    May 14, 2011
    68
    0
    Hi,

    I opened up an inverter board for an LCD screen. I thought I would use a multimeter to check all resistors to see if any of them were not working.

    I found two SMD resistors near each other, type '103' which is 10k but the reading I got was about half of that. I checked other '103's on the board and they displayed the value correctly.

    The board is not connected to any power supply. Are they broken?
     
  2. MCU88

    Member

    Mar 12, 2015
    360
    35
    You cannot measure resistors while they are in circuit. The reading will be wrong. You need to remove them from the circuit first.

    It is very rare for an resistor to be faulty... (generally speaking) ...
     
    Lundwall_Paul likes this.
  3. crutschow

    Expert

    Mar 14, 2008
    13,014
    3,234
    Any other resistances in parallel with the resistor being measured will affect the measured resistance. That's why, in general, you cannot measure resistors in a circuit and expect the correct value, unless you know there're no other resistive paths in parallel with the resistor.
     
    Lundwall_Paul likes this.
  4. Lundwall_Paul

    Member

    Oct 18, 2011
    220
    19
    Now on the other side of the coin if they read greater then 10k they most likely are bad.
     
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