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  1. serbar

    inductive position sensor sine to square wave conversion

    zappedagain, Thanks for tip. Im sorry, but even if is what you say i think the distributor should not be doing this because the current is not changing versus time. Plus the distributor has no mechanical contact breaker in primary circuit, it has just and inductive sensor inside, and that...
  2. serbar

    inductive position sensor sine to square wave conversion

    Hi. It works fine. The osciloscope doesnt show the noise anymore with inductive sensor. Thanks a lot. But now i have another issue: I am doing a DYI automotive ignition coil driver. I made the circuit exactly like in this link (first picture)...
  3. serbar

    inductive position sensor sine to square wave conversion

    Hi. I installed an external inductive sensor atacched to the crankshaft of a car with a tooth wheel with a two teeth gap to detect top dead center. I converted the sine output from sensor to square wave with the atacched squematic using a LM 393. I am monitoring it with an arduino mega 2560...
  4. serbar

    injector driver

    Thanks for reply. LM1939 can be used for saturated driver too.
  5. serbar

    injector driver

    Hi. I need to build an injector driver circuit for two bosch injectors: 0 280 155 965 and 0 280 1150 749. Both are high impedance injectors (15 ohm). My choice is using an LM 1949 as injector driver. My question is: can i use peak and hold mode with this injectors or do i need to drive them...
  6. serbar

    Damaged usb interface

    Thanks for information. So i think most opinions point out to a capacitor for noise supression? If i place a wire instead of the component which of the three terminals should be connected with? Thanks.
  7. serbar

    Damaged usb interface

    Sorry. Here is the atached picture of the PCB. Thanks.http://files.engineering.com/getfile.aspx?folder=339aa36f-af8b-4ed2-9afb-b438ec73893b&file=SB1.JPG
  8. serbar

    Damaged usb interface

    Hello. I have an usb interace from a car diagnostic tool that i damaged. I am trying to fix this since the new one is very expensive. Dont have welding skills on PCB so contacted a skiled friend to do this job. Let it fall down and some SMD components got loose from their welding but i could...
  9. serbar

    Power Loss measurment on Eddy current dynamometer

    Ok. From what you said, My conclusion: The transmission losses are estimated ( calculated) in every chassis dynos based on coast down time and speed of the rollers among others. Am i right? Thanks.
  10. serbar

    Power Loss measurment on Eddy current dynamometer

    Yes i understand, but i have seen people in Eddy dynos doing the "coast down procedure" after a test, and i want to know what kind of data and what is behind the procedure to calculate power losses. Can you clearly tell me that? Thanks.
  11. serbar

    Power Loss measurment on Eddy current dynamometer

    So roll down time and variation of roller speed (acceleration) can be used to calculate kinetic energy and then power losses. The dynamometer computer do this if we input car and driver weight is it right?
  12. serbar

    Power Loss measurment on Eddy current dynamometer

    Wanted to say dynamometer rollers. Sorry.
  13. serbar

    Power Loss measurment on Eddy current dynamometer

    Hello. I want to know more about dynamometers, namely Eddy current dynamometers. My issue is Power Losses Measurement, i know that after reach max desired rpm one should press the clutch till the car stops and the computer in the dyno take the power loss values. But when you press the clutch...
  14. serbar

    555 duty cycle modulator

    Don t know if i have to create a new tread for this, if yes tell me please. My question is: Just for curiosity i want to know the power dissipated by the elctrovalve. So i need to know current and Voltage. I searched in some websites for calculations of a mean voltage and current in PWM drived...
  15. serbar

    555 duty cycle modulator

    Yes. I will try with a FET too. Thanks.
  16. serbar

    555 duty cycle modulator

    Ok i now have much less variation in voltage (12 V with 0% duty cycle and 10 V with 100% duty cycle), and what i did different was: 1. Use a TIP31C transistor; 2. Increase the current button in my power suply since it was giving me a very low current suply (i think it was the main problem)...
  17. serbar

    555 duty cycle modulator

    Here is the circuit schematic i made, and two hand made oscilograms at 50% and 10% duty cycle with osciloscope leads at 12,5 ohm resistance terminals (same resistance as an electrovalve i want to test but don t have on here right now so i put a regular 470 ohm pot). As i said i want to test...
  18. serbar

    555 duty cycle modulator

    The osciloscope image on the terminals of an electrovalve of this type is on page 4 of the atached document, bottom right, figure 7, for two diferent duty cycle situations. Observe that the "on" voltage value is always batery voltage regardless of duty cycle...
  19. serbar

    555 duty cycle modulator

    Ok my problem now is: I want to have more or less 500 mA with 12 V on the electrovalve, so i need a transistor since LM393 output is max 5 mA, no problem. But with the configuration "electovalve load in series with transistor colector-emitter circuit" i don t have constant 12 v on electrovalve...

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