DC Voltage clipper - safeguard the measurement card.

Discussion in 'General Electronics Chat' started by V.JAIKANTH, Mar 19, 2012.


    Thread Starter New Member

    Mar 19, 2012
    I have few DC voltages to be measured which are less than 10V.
    For measuring I'm using the data acquisition module which has the range of 0 to 10 V.
    In case at any situation if the DC voltages goes more than 10 V they damage the DAQ device.
    so I want voltage clipper circuit that passes as it is ..only less than 10V.
    at any moment if the signal is more than 10V the voltage must be clipped for safeguarding my DAQ device.

    Any circuit/ advise .. please share !!
  2. evilclem

    Active Member

    Dec 20, 2011

    MOV to ground. Place a resistor inline with your DC signal on the signal side of the varistor (not the data acquisition module side), this will limit current through the varistor to prevent it burning out whilst the varistor will keep the voltage within the limits of the data acquisition module. Note that this resistor may affect your signal if you're not careful, use a fuse instead of resistor if you don't want to use a resistor.
  3. russ_hensel

    Distinguished Member

    Jan 11, 2009
    A diode to a 10 volt reference ( the supply voltage perhaps ) is a standard approach. The diode is usually biased off. You will need an input resistor ( or input impedance ) prior to the diode. Voltage will go to 10 v + 1 diode drop. This is usually Ok, but check the data sheet.