Signal divider

Discussion in 'General Electronics Chat' started by millard, Aug 9, 2005.

  1. millard

    Thread Starter New Member

    Aug 9, 2005

    Electrics is not my strong point I'm more of a mechanic, I need to take an electrical signal which is counted and make 2 pulses appear as 1.

    If you are wondering what I'm doing: I'm trying to use a motorcycle rev counter on a car engine as it is considerably more compact but as I'm using a V8 it fires twice as many times as the 4 cylinder engine it was designed for.

    I guess its a very simple circuit, all and any help greatly appreciated.


  2. Ron H

    AAC Fanatic!

    Apr 14, 2005
    The devil is in the details. If you had logic-level pulses available, all you would need is a toggle flip-flop, which divides frequency by two. The hard part is getting from whatever your input is, to a logic level pulse. This is going to be difficult without a hands-on look at what you have.
  3. millard

    Thread Starter New Member

    Aug 9, 2005
    All I know is that a 12v pulse comes from the distributer to trigger the coil to fire a 50000v charge back to the distributer, that is then sent to each spark plug in turn.

    what is a "logic level pulse"?
  4. thingmaker3

    Retired Moderator

    May 16, 2005
    A logic level pulse is in the ballpark of three to five volts when high and les than half a volt when low.

    If you you can tap off the 12v coil i/p and use a voltage divider to bring the sampled pulse down to this level, then you might be able to divide frequency with the flip/flop and then amplify flip/flop o/p for the tachometer to use.

    You will need to know about voltage dividers, also flip/flops, simple amplifiers, and possibly de-bouncing.

    voltage dividers

    Flip/flop used to divide frequency by two

    Table of Contents for Amplifiers Chapter