I need a circuit built

Discussion in 'General Electronics Chat' started by dto, Apr 25, 2011.

  1. dto

    Thread Starter New Member

    Apr 25, 2011
    6
    0
    Anyone out there willing to build me a circuit? I will pay for it also.
     
  2. oidium45

    Active Member

    Apr 24, 2010
    130
    8
    Dude, that would seriously take you 5 minutes..
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Not sure what you're trying to do.

    What is it that you are trying to do?
     
  4. dto

    Thread Starter New Member

    Apr 25, 2011
    6
    0
    I'm an automotive service tech. I need this component built to boost a signal of a sensor. Now why do I not replace the sensor? Because, doing so would require 15 hours of labor. The signal from the sensor is 'weak'.
     
  5. Jaguarjoe

    Active Member

    Apr 7, 2010
    770
    90
    The inputs to the op-amp are backwards. Your gain setting resistors should go to pin 2 and your input from the VSS should go to 3.
    One of the power supplies is backwards. Pin 4 should get a negative supply and pin 7 should be positive.
    There are more modern op-amps to use than the 43 yo 741.
    Most likely the VSS signal starts at 0 volts and goes positive. There are no negative excursions. You can find a single supply rail to rail op-amp and eliminate one of your 6v batteries. Change the other battery to 9v and you can use a common PP3 battery to power it if the PCM can take the higher voltage.
     
  6. dto

    Thread Starter New Member

    Apr 25, 2011
    6
    0
    I don't know much about electronics. I got the schematic from a different fellow who made that same device his vehicle. If there is a better method, or technique it'd be appreciated.
     
  7. dto

    Thread Starter New Member

    Apr 25, 2011
    6
    0
    The sensor also puts out negative excursions. Samples provided.
     
  8. dto

    Thread Starter New Member

    Apr 25, 2011
    6
    0
    Sorry, forgot to attach
     
  9. Jaguarjoe

    Active Member

    Apr 7, 2010
    770
    90
    Ok, if you want the negative output you will need to stick with dual batteries.

    As I said before the pins are not correctly shown in the drawing.
    Pin 2 is the (-) input, it gets the junction of R1 and R2.
    Pin 3 is the (+) input, it gets the VSS signal.
    Pin 4 is the (-) power connection. It gets (-) 6 volts, referenced to gnd.
    Pin 6 is the output, it is ok.
    Pin 7 is the (+) power connection. It is ok.

    This explains how it works:

    http://www.allaboutcircuits.com/vol_3/chpt_8/5.html
     
  10. dto

    Thread Starter New Member

    Apr 25, 2011
    6
    0
    I decided to build the circuit myself. But, i am a little bit confused. I've 2 sensor wires. It appears, one sensor wire is cut and fed in to the amp. But the other wire looks like its spliced in to the other wires?
     
Loading...