1. Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
    Dismiss Notice

Understanding Electronics Basics #1

Discussion in 'General Electronics Chat' started by cowboybob, Feb 16, 2012.

  1. cowboybob

    cowboybob Well-Known Member Most Helpful Member

    Joined:
    Oct 22, 2011
    Messages:
    3,023
    Likes:
    477
    Location:
    James Island, SC
    Web access is still iffy. In for now.

    One way to consider AC and DC together, is this:

    An AC signal is presumed to vary, UP and DOWN in potential, as a sine wave, in a positive and then negative fashion, varying around ZERO volts, or GROUND.

    A DC potential is, generally, a stable POSITIVE (or NEGATIVE) potential greater than (or lesser than) GROUND.

    By combining an AC signal with a DC potential, the GROUND that the AC oscillates above and below is altered to the potential of the DC level.

    The oscilloscope demonstrates this phenomenon.


    It's 2320 your time Graham, See ya on the morrow.
     
  2. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

    Joined:
    Oct 30, 2010
    Messages:
    9,916
    Likes:
    1,097
    Can you grasp this:

    If you had two sine wave generators (1V p-p) in series and looked at the output and vary the phase of one of the oscillators, you can vary the amplitude from 0V to 2V p-p.
     
  3. Muttley600

    Muttley600 New Member

    Joined:
    Jan 16, 2012
    Messages:
    681
    Likes:
    5
    Location:
    Worcestershire, England
    Yep, I'm getting that bit now :)
     
  4. dave

    Dave New Member

    Joined:
    Jan 12, 1997
    Messages:
    -
    Likes:
    0


     
  5. Muttley600

    Muttley600 New Member

    Joined:
    Jan 16, 2012
    Messages:
    681
    Likes:
    5
    Location:
    Worcestershire, England

    not until I get the sim done, need to get ready for work so will play later, have a good day guys

    Edit: still trying to understand but getting nowhere fast......sigh

    What is the phase? I have tried varying it on one input but it doesnt seem to change anything?

    I know 500m will give me a 1v sinewave as in 500 either side of gnd

    [​IMG]

    & I understand that a DC voltage will lift/lower the signal
     
    Last edited: Feb 17, 2012
  6. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

    Joined:
    Oct 30, 2010
    Messages:
    9,916
    Likes:
    1,097
    Phase is in degrees, so try 0, 45, 90, 180, 270
     
  7. cowboybob

    cowboybob Well-Known Member Most Helpful Member

    Joined:
    Oct 22, 2011
    Messages:
    3,023
    Likes:
    477
    Location:
    James Island, SC
    OK. Site back up. YEAH!!

    I'll make a circuit w/ 2 AC sources so phase can be demonstrated.

    Manana.
     
  8. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

    Joined:
    Oct 30, 2010
    Messages:
    9,916
    Likes:
    1,097
    In order to see phase on a scope, you can't use auto-trigger. You do need to display two generators simultaneously. Or the result and one generator. One generator has to be reference.

    You can see the effect with an AC voltmeter.
     
  9. Muttley600

    Muttley600 New Member

    Joined:
    Jan 16, 2012
    Messages:
    681
    Likes:
    5
    Location:
    Worcestershire, England
    I'll have a play with phase again later, as site was down yesterday I was reading up on AC, correct my understanding where it is wrong please :)
    In DC you set the voltage on battery for sim, that's it.
    In AC, Ampitude (p-p) is the voltage, so there's no direct voltage setting like DC, Ampitude/frequecy & phase all come under the wave setting.
    We can add DC to lift or lower the AC signal called bias dependant on -/+
    We can convert an AC signal into a DC signal with a full wave rectifier

    Hers what I found interesting with AC, because it moves both directions in travel, hence we get a - side & a + side, only the + is real power, the - side is energy that returns that cannot be used by load but has to be accounted for in circuits as it is present, so the negative side can be used for the mag in inductors while the + side is running on the coil as real power, but the - side is being used to delay it (phase-duty of wave cycle) I take it without reading back that was for voltage?
    A similar story for caps but with current, so the - side is where we are getting all this heat from.

    Hopefully you can help my clean up my understanding, but I'm a bit further forwards, more importantly I think I now understand how inductors/capicitors work, that's two components down, still need to understand how transistors work but I feel goooooood :)

    Morning to you both when you get up :)
     
    Last edited: Feb 17, 2012
  10. Muttley600

    Muttley600 New Member

    Joined:
    Jan 16, 2012
    Messages:
    681
    Likes:
    5
    Location:
    Worcestershire, England
    Need to work out how to get 2 channels on sillyscope now
     
  11. cowboybob

    cowboybob Well-Known Member Most Helpful Member

    Joined:
    Oct 22, 2011
    Messages:
    3,023
    Likes:
    477
    Location:
    James Island, SC
    View attachment 61207
    Yes. Very good.

    Yes, but an emphatic no.

    BOTH "swings" (positive AND negative) of the AC signal represent power. Any change in potential away from ground is energy that can be used or observed. As you say, it is merely going one direction or the other in the circuit.

    Now, If you rectify the AC (with one diode), then yes, 1/2 of (either the positive or negative swing) of the signal is blocked. So, in this case, 1/2 of the power is eliminated. However, in the case of a Full wave rectifier arrangement, both swings are utilized.

    Morning, BTW...

    Check this out...

    View attachment 61205 and this View attachment 61209 This too View attachment 61211

    (Note slight reduction in amplitude of rectified signal: this is due to internal resistance of the diode).
     
    Last edited: Feb 18, 2012
    • Like Like x 1
  12. Muttley600

    Muttley600 New Member

    Joined:
    Jan 16, 2012
    Messages:
    681
    Likes:
    5
    Location:
    Worcestershire, England
    going to need to clarify this bit, I understood it to be 2 lots of power, one could power load & one couldn't, but it could be used for components if that makes sense.

    so if you flip wave over into DC it is stable & cannot power components, hence having to turn DC back into AC to deal with then flip back to DC

    Does that make sense, please carrying on correcting me [​IMG]


    totally understand this, simplified by diagrams, great job [​IMG]

    Feel free to show me how to swop wave over while I put new sim together [​IMG]

    It must be sinking in, on second sim, I automatically changed it to 5m on time line [​IMG]
     
    Last edited: Feb 18, 2012
  13. cowboybob

    cowboybob Well-Known Member Most Helpful Member

    Joined:
    Oct 22, 2011
    Messages:
    3,023
    Likes:
    477
    Location:
    James Island, SC
    Power is there, irrespective of the direction of flow or its potential (+ or -). I say again: Power is there, irrespective of the direction of flow or its potential (+ or -).

    DC is also power. DC makes your bike's lights light, relays close, iPhones works, etc... The whole business of converting DC to AC and back to DC is an electronic method to "buck" (reduce) or "boost" (increase) a voltage (AC or DC). This is just easier to do with AC.

    Again, ANY voltage GREATER than (or LESS than) zero is a form of energy (AC or DC), and will do work.

    (My emphasis)

    Not sure what your asking.
     
    Last edited: Feb 18, 2012
  14. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

    Joined:
    Oct 30, 2010
    Messages:
    9,916
    Likes:
    1,097
    I have to interject, the concept of negative power.

    Positive power is power dissapated.
    Negative power is power generated otherwise...

    If you had a 10 MW generator and 1 million customers consuming 10,000 W
    10 MW = 1000 * 1,000,000
    0 = -10MW + 1000 * 1,000,000

    or
    Power consumed = power generated
     
  15. Muttley600

    Muttley600 New Member

    Joined:
    Jan 16, 2012
    Messages:
    681
    Likes:
    5
    Location:
    Worcestershire, England
    Yep, get that bit [​IMG]
    This is where I got my idea of useable power for load & power for components

    [​IMG]

    & that bit [​IMG]

    & that bit [​IMG]

    I was trying to do this, maybe jumping ahead of myself
    [​IMG]

    [​IMG]

    I was jumping ahead weren't I, carry on [​IMG]
     
  16. Muttley600

    Muttley600 New Member

    Joined:
    Jan 16, 2012
    Messages:
    681
    Likes:
    5
    Location:
    Worcestershire, England
    [​IMG] CBB [​IMG] so what does that mean in english KISS [​IMG]
     
    Last edited: Feb 18, 2012
  17. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

    Joined:
    Jan 4, 2007
    Messages:
    21,185
    Likes:
    644
    Location:
    Ex Yorks' Hants UK
    hi,
    This Thread has drifted well off the '12DC' topic, it would be a good idea to start a new Thread with an appropriate Title/s, this would help members to identify the Topic/s under discussion.

    Moderation. E
     
  18. cowboybob

    cowboybob Well-Known Member Most Helpful Member

    Joined:
    Oct 22, 2011
    Messages:
    3,023
    Likes:
    477
    Location:
    James Island, SC
    Graham,

    Eric's right.

    But this is your thread. I'll go to whatever new one you make.
     
    Last edited: Feb 18, 2012
  19. Muttley600

    Muttley600 New Member

    Joined:
    Jan 16, 2012
    Messages:
    681
    Likes:
    5
    Location:
    Worcestershire, England
    Shall I put new thread for understanding basics then?
    & keep this one for the project
    Easy on either way, it's all the same thing to me but it is turning a into a lot of pages, think its a bit much to ask any mod to try & sort out the different bits so far.

    Does it need to go under 'general elec'

    Could a mod please pull this from post #590 onwards & put it where it is meant to go under title 'Understanding Basics'

    Thanks
    Graham

    While we wait, where were we, just had nice walk in countryside with bobby, no, that's not it is it, you were just about to carry on explaining where/what I had misunderstood & carry on telling me about AC :)

    You prob see it differently to me at the moment as I'm just seeing this as playing with waveform variations

    Moved: Moderation,E
     
    Last edited by a moderator: Feb 18, 2012
  20. Muttley600

    Muttley600 New Member

    Joined:
    Jan 16, 2012
    Messages:
    681
    Likes:
    5
    Location:
    Worcestershire, England
    Wow, that was quick, I thought it would take ages

    Thank you Eric
    Graham
     
    Last edited: Feb 18, 2012
  21. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

    Joined:
    Oct 30, 2010
    Messages:
    9,916
    Likes:
    1,097
    Just jumping on the train again.
     

Share This Page