The simple workings of a circuit

Discussion in 'General Electronics Chat' started by circuitsbaffleme, Sep 29, 2011.

  1. circuitsbaffleme

    Thread Starter New Member

    Sep 29, 2011
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    Hi,

    EE courses always confused me, but I am fascinated by the way electronics work. Is there a place that could show me the simple inner workings of a circuit such as a radio amplifier? In a light and switch circuit it's easy... the power comes out of the battery, through the switch, into the bulb which heats up due to it's resistance and turns bright, the power continues back to the battery, etc.

    I'd like to understand how something like a radio receiver works in the same way - what happens inside each component to make the magic. Something like this... the power comes out of the source, then goes into the [whatever... capacitor]. It builds up a charge on a surface until x happens, and then jumps across the gap, which does xxx), and then into the [blank] where this happens, etc (and what purpose that served).

    I know this is kind of sketchy, but each component does something and when strung together the right way, they perform a function. In a bigger circuit like a transceiver, I know there are stages and each stage does something to allow someone to receive or transmit. I can grasp the concept of a stage, and even what each stage does overall, but I want to understand how the electrons move from one component to the next and what happened when they did to make it all come together. Is there a way to learn this for a simple circuit (more than a lightbulb or motor)?

    Thanks,
    Mike
     
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    To understand a big thing you first need to understand all the small things that make it up. A radio amplifier is only simple once you know all the pieces cold and have probably see that amp 100 times already.

    Sorry there is no quick way. You may want to start with the tutorials located at the top of this web page. Come on back and ask any specific questions you run into.
     
  3. circuitsbaffleme

    Thread Starter New Member

    Sep 29, 2011
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    Thanks Ernie, good point. Maybe I am looking at something that's too big. I understand the resistance in a bulb makes it glow and therefore produce light, or that a variable resisitor allows less electricity into a motor so it goes slower depending on the setting. It is that same undrstanding I am trying to gain from some other simple circuits. I am amazed that these little pieces do something when assembled in a specific order, and perhpas something else when assembled differently. I just don't understand why, so figure if I can trace the "what's happening at each piece", it will be come clearer.

    Mike
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    In some ways you are correct. You have to understand in full detail how each and every component works, resistor, capacitor, diode and transistor. But that alone is not enough. When you put two components together, a resistor and capacitor for example, the synergy can be quite different. There is a lot more to learn than just component behavior. Keep on learning is the best advice I can offer.
     
  5. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    Actually, the good news is at a certain point the parts begin to "chunk together" (my term), meaning you don't have to know how every widget inside works.

    For example: there is a common part (actually thousands of them) called an "op amp," short for operational amplifier. They are usually integrated circuits, or just chips. While you could crack open the data sheet and see if they have the circuit diagram in there, no one ever does that. The whole circuit is "chunked" into a block, and you just need to consider how the chunk (block) works, not it's pieces.

    (Aside question: what is the alternative to an operational amplifier? A non-operational amplifier?)
     
  6. Markd77

    Senior Member

    Sep 7, 2009
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    Maybe this would be useful:
    It's a circuit simulator, not the most accurate, but it gives the general idea.
    http://www.falstad.com/circuit/
    There are some simple circuits in the menu, but you can draw your own as well and see what is happening.
     
  7. circuitsbaffleme

    Thread Starter New Member

    Sep 29, 2011
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    That is really cool, and is somewhat half my solution! I am curious to see "inside" the component (which is sort of there by virtue of the flow in the circuits). I'll study that simulator some more and see what I can get out of it.

    Mike
     
  8. davebee

    Well-Known Member

    Oct 22, 2008
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    Why not look at crystal radio receivers? They are a great way to get exposed to many of the concepts of radio without getting buried in too many math and component details.
     
  9. Adjuster

    Well-Known Member

    Dec 26, 2010
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    It may help you to rid yourself of some misconceptions, or at any rate inaccurate colloquial ways of describing electricity. For instance, strictly speaking the quantity which circulates in electric circuits is current, not power. We may use words like power more loosely in everyday speech, but in technical contexts this becomes confusing.

    Getting properly to grips with some concepts like electric current, potential, power, and energy would a good start. The relationships between them might be the next steps, starting with Ohm's law, Kirchhoff's Laws, and going on... as far as you care to take it really.

    All of this may sound quite boring, but really it is hard to describe what (say) a transistor does or how, if we are at a level of understanding where "...the power continues back to the battery..."
     
  10. CraigHB

    Member

    Aug 12, 2011
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    Current is a hard concept to fully understand and conceptualize. You've got negatively charged particles moving one way or sometimes not and postiviely charged particles moving the other way or sometimes not. Still not sure if I understand it correctly after years of working with electronics and a degree in EE. I just go by the math and the conventions then leave it at that.

    For someone learning, I'd say not to spend too much time trying to understand the actual flow of particles, that will give you a headache. Rely on the conventions and math to provide an understanding.
     
  11. Adjuster

    Well-Known Member

    Dec 26, 2010
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    Perhaps understanding these concepts fully is a tall order, but it is helpful to get to the point where the distinctions between the basic quantities are understood, if only to avoid unfortunate mistakes with ammeters across the supply.
     
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