Inductive sensor

Discussion in 'The Projects Forum' started by selfbg, Apr 7, 2011.

  1. selfbg

    Thread Starter Member

    Jun 11, 2010
    Im building something that looks like rev counter. This is the first time im using inductive sensor. The signal from the sensor is passed to Schmitt trigger. The problem is what king of protection to use? Im thinking about 2 clipping diodes to cut the sine to 0 and 5 volts. The problem is that in practice the low voltage is -0,7 which is bad for the CMOS IC (I thing so??). Is there any way to limit the sine to 0-1 and 4-5 volts? (I want to avoid using battery, this is the only method that i know).

    Thank in advance :)
  2. Bernard

    AAC Fanatic!

    Aug 7, 2008
    Most of the CMOS ICs have clamps to gnd. and 74C14. For protection might add a 1 k Ω in series with input to limit clamp current to no more than 20 mA, give or take. -.7V should be no problem.
  3. hgmjr

    Retired Moderator

    Jan 28, 2005
    Can you post your schematic here so that we can see what you have at this point?