Op amp for logic level amplification

Discussion in 'General Electronics Chat' started by cstewart000, Aug 6, 2012.

  1. cstewart000

    Thread Starter New Member

    Aug 6, 2012
    High I have a device outputing a 0 to 1v square wave. I need to bump it to a 0 to 5v wave to get my MCU to recognise the logic. is an op amp a suitable solution. I can only find audio related applications.

    Thanks for putting me on track.

  2. WBahn


    Mar 31, 2012
    There are a number of ways to do it. You can get level shifters specifically designed to due logic level translation. You could use an o-amp circuit, or you could use a transistor switch.

    How fast do you need this to work? What is the shortest time between transition events? How much time can it take in making a transition?
    cstewart000 likes this.
  3. ramancini8

    Active Member

    Jul 18, 2012
    A simple transistor level shifter suits you best; use a 2N2222 transistor, a 430 ohm collector resistor, a 5 volt Vcc, a 1.6K base resistor. As long a the input signal switchesw fast the output signal will be clean. The signal is inverted, so you may need two stages for inphase output; in that case the second base resistor should be 8.2K.
    cstewart000 likes this.
  4. cstewart000

    Thread Starter New Member

    Aug 6, 2012

    looks about 10 micro seconds. I am trying to run a digital caliper. I have found many sources talking about how to shift it up but I cant get anything to produce the desired result in simulation.

    Thats why I am asking gurus
  5. cstewart000

    Thread Starter New Member

    Aug 6, 2012
    I am sure that I tried a very similar circuit with no luck. I probably set the resistor values wrong.

    How do I invert the signal?? can you recommend an inverting logic chip for this app?

    will the rise and fall times here mess up the communication?

    Thanks again I have attached the LTspice files
  6. Ron H

    AAC Fanatic!

    Apr 14, 2005
    You can do it like this:
    cstewart000 likes this.
  7. cstewart000

    Thread Starter New Member

    Aug 6, 2012
    Thanks for that mate.

    What a a great help. I deffinately had a more convoluted solution in mind.

    I guess it follows that If you do something and it goes out of phase do it again until its back in phase. :D
  8. crutschow


    Mar 14, 2008
    Coming up with a design is not necessarily the hardest part. Getting the simplest design to do the job is where the real work is done. ;)