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Misc Electronic Questions

Discussion in 'General Electronics Chat' started by Billy Mayo, Apr 4, 2013.

  1. Billy Mayo

    Billy Mayo Member

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    The solid state relay is powered by 120 volts AC , the signal of the solid state relay goes direct a controller PIN

    What does the solid state relay do?

    Solid State Relay pic#1.jpg

    Op-Amp Detector, What does it do ?

    Op-amp Dector circuit pic#1.jpg

    Here is an RC network in the feedback section of an op-amp , what does it do?

    RC feedback network pic#1.jpg

    This IC voltage Detector, goes direct to the Micro-controllers RESET pin, what does the IC voltage detector do? once the VCC is to low it Resets the Micro-controller?

    If there is a short and the VCC is low all the time , it's just going to keep Resetting the Microcontroller right?

    Voltage Dector for Microcontroller.jpg

    What does these LF13333N Switches do?

    When they have an square waveform on the input pin of a LF13333N the output of the LF13333N switch changes the Amplitude of the square waveform i have noticed

    LF13333N Switch pic#1.jpg
    LF13333N Switch pic#2.jpg

    What does the Diodes do? The Nor gates have these Diodes for what?

    Nor gate with Diodes pic#1.jpg
    Nor Gate with Diodes Pic#2.jpg
     
  2. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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  3. audioguru

    audioguru Well-Known Member Most Helpful Member

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    If the resistance of a short is only 0.5 ohms and causes the 5V supply to drop to 2V then using Ohm's law: 2V/0.5 ohms= 4A or 4000mA.
     
  4. dave

    Dave New Member

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  5. Billy Mayo

    Billy Mayo Member

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    Yes true

    I just don't get the water analogy of how a low water level can have very Big or large water Flow or pressure

    Current = water flow or water pressure rate

    how can you have a small tank of water that's water level is 1/16 inch and have the water flowing at a very fast speed that can cause damage

    SHORT = Very low voltage , VERY high current = IC chips gets HOT

    SHORT= Very low water level, VERY fast water flowing, Won't break a water pipe or put out a fire
     
  6. Billy Mayo

    Billy Mayo Member

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    There is a lot of waveforms when I'm probing around on circuit boards at work that are very hard to trigger it seems with the oscilloscope

    They keep "free running" even at any setting on my trigger on the oscilloscope

    I even change the volts/per knob and adjust the trigger level and I still can't get the waveform to sit still , its keeps "free running" , I might be able to slow it down some , but it keeps Free running

    The Trigger mode is on channel#1 , Trigger is in Auto mode

    What Can I do? and why won't these waveforms trigger? are they to fast or what?
     
  7. Billy Mayo

    Billy Mayo Member

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    What does those peak detector op amps do for digital TTL or CMOS logic signals? what are the peak detector op amps used for?
     
  8. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    Don't use auto-trigger. Use the level/slope controls or external triggering off of a related signal.

    PS: Did you read your PM?
     
  9. Billy Mayo

    Billy Mayo Member

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    I do use the level slope controls and the waveform is still in free running , I can't get it to stop

    I'm not sure why these waveforms I can't seem to stop, are they to fast?
     
  10. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    I asked earlier about an instruction manual. Some scope have difficulty triggering on channel #1 just based on the scope design.

    If you have many periods of the waveform visible, it's usually more difficult to trigger on it as well.
     
  11. Billy Mayo

    Billy Mayo Member

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    Yes it does help when I only have one or 2 periods when triggering thanks
     
  12. Billy Mayo

    Billy Mayo Member

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    1.) The Diodes are for when the NOR gate is in the OFF state
    When the NOR gate is in the ON state is a time constants from the capacitor and resistor and when the OFF state is doesn't go through the resistor, is goes through the diode

    2.) The Diodes protect it from creating a short circuit since the NOR gates are connected in Parallel

    Nor gate with Diodes pic#1.jpg
    Nor Gate with Diodes Pic#2.jpg


    This is a comparator op-amp
    When a Logic HIGH is on the input , the output is a LOW
    When a logic LOW is on the input, the output is a HIGH
    The Diode is to set the hysteresis

    Voltage Dector for Microcontroller.jpg

    I'm not sure when they didn't use a Schmitt invertor instead

    I guess the diode sets up a DC offset voltage?
     
  13. Norator

    Norator New Member

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    I get the feeling you're in over your head.

    In your situation I'd find ways to independently confirm what the people at work tell you. People may observe things correctly but drawing correct conclusions about 'why?' is more difficult and sometimes they come up with the most outlandish ideas.
    This confirmation process also helps when troubleshooting so that you don't go very far off on the wrong path.

    Here's a thought experiment for you.
    There is a wire coming out of a box in a very old house wall. It is insulated but the color has been painted over.
    How to tell if it goes to a neutral, a ground, a hot lead or one side of some kind of load?
    How to tell if the connections back to the panel have integrity?
    What test instruments do you need? Why these in particular?

    Another question:
    What is more likely to correctly predict LED brightness, LED current or LED voltage? How do you know? What is your reasoning?

    BTW, some people you work with may be there because they have merit and others may be 'political appointees' in the broadest sense.
    Avoid the second group if you can identify them - they are probably incompetent and almost certainly proud, both at the same time, and they can get you fired for cause or without cause.

    And if there is ever a circuit problem and someone says "It's a ground loop" ask them for a diagram showing where the current goes. Expect a lot of hand waving at this point. :(
     
    Last edited: Apr 29, 2013
  14. Billy Mayo

    Billy Mayo Member

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    I posted the wrong pictures he is the right one

    This is a comparator op-amp
    When a Logic HIGH is on the input , the output is a LOW
    When a logic LOW is on the input, the output is a HIGH
    The Diode is to set the hysteresis

    Op-amp Dector circuit pic#1.jpg
     
  15. Billy Mayo

    Billy Mayo Member

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    What do the 2 resistors do? the ones I circled, I see these a lot in logic circuits, It's not just a voltage divider, its like it's pull up the logic signal to a reference zero

    Does the 2 resistors level shift the logic signal?

    Does the 2 resistor Clamp the Logic signal to clip at a certain voltage?

    Why is the VCC +5 and the VDD - 15 volts? why not -5 volts or zero volts, why -15 volts?

    Click here:
    Logic Resistors pic#1.jpg
     
  16. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Your schematics are useless because they do not have a DOT where a wire joins another wire.
     
  17. Billy Mayo

    Billy Mayo Member

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    Yes true, The Designer at my work didn't put in the junction nodes

    But What can you make out of it from my questions please would help me out a lot
     
  18. Billy Mayo

    Billy Mayo Member

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    The High state is +5 volts and the low state is -15 volts, why not zero volts? why is it -15 volts?
     
  19. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    I'll bet that +5 is a common logic level and a Vdd of -15 is available.

    Op amps have LOTS of trouble with voltages at their supply rails. Only recent OP amps are doing a good job at it. Older OP amps/comparators can only swing within say 1.2 V of a power supply rail.
     
  20. Billy Mayo

    Billy Mayo Member

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    What u mean by this? trouble in what way?

    1.2 Volts Positive and negative only 1.2 volts in either direction?
     
  21. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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