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Susan Brown

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Viewing 15 posts - 1,546 through 1,560 (of 1,968 total)
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  • in reply to: Moved: dryer no heat #15543
    Susan Brown
    Keymaster

      Hi Robert,

      You’ll need to give me more details on this. Is this related to a Question on the Midterm? (Question 9?) If so, please rewatch the last video in Unit 6 for a similar, but not identical, scenario. Let me know!

      in reply to: Series circuit #15538
      Susan Brown
      Keymaster

        Great! Thanks for using the Forums 🙂

        in reply to: Voltage drop and equivalent resistance #15526
        Susan Brown
        Keymaster

          Hi Kenneth,

          These loads are in series in one circuit. Will the current change throughout the circuit? (if you think “yes”, then review the first video in Mod. 3, unit 5).

          You do need to use the equation E = I x R to calculate each voltage drop, but you have to use the correct value for the current (I) to get the correct answers.

          in reply to: diagramsu #15522
          Susan Brown
          Keymaster

            Hi Rees,

            Thanks for posting in the Forums!

            A great video to rewatch that shows these types of calculations is the last video in Mod. 3, unit 3 on the heat generated by a loose connection. Watch that, and re-create the calculations in your notebook. Then look at the questions in the Unit 8 quiz and see if they make more sense.

            If you don’t follow something we’re showing in that video, please let me know and I’m happy to help you further.

            in reply to: Question #9 on refrigerator repair refrigerant cycle. #15519
            Susan Brown
            Keymaster

              No problem! Sam (who is a mister) is one of the folks helping you. One of us will get back to you ASAP.

              in reply to: Question #9 on refrigerator repair refrigerant cycle. #15516
              Susan Brown
              Keymaster

                Hi Samuel – could you please be more specific about which question you’re referring to? Thanks!

                in reply to: Test question help please. #15515
                Susan Brown
                Keymaster

                  Hi Michael,

                  The fact that the terminal is labelled NO, and it’s in the “normal” state, is what tells you that the switch is open. And that is why you would measure 12vdc.

                  Does that answer your question?

                  in reply to: Module 3 Unit 5 #15512
                  Susan Brown
                  Keymaster

                    Hi Ryan,

                    Thanks for posting in the forums!

                    One of the keys when looking at schematics is to “see” it from the electron’s point of view. Electrons don’t “see” bends in a wire, for example, like we do when looking at a diagram.

                    That’s one reason we suggest doing the “Zen trick” on the loads, when you aren’t sure if they are in series or parallel. Try doing that on the light bulb – “become” the light bulb – both with the switch open and then the switch closed. Does that help you figure it out? Let me know!

                    in reply to: Module 3, Unit 8, Quiz question 6&7 #15506
                    Susan Brown
                    Keymaster

                      That’s correct! (I’m going to hide those answers so future students won’t see them.)

                      in reply to: Fundamentals – Module 3 Unit 5 Question 11. #15481
                      Susan Brown
                      Keymaster

                        Correct!

                        There’s a lot to learn in the Basic Electricity module, and it can be quite a challenge. Please feel free to ask more questions here as needed – we’re glad to help!

                        in reply to: Fundamentals – Module 3 Unit 5 Question 11. #15467
                        Susan Brown
                        Keymaster

                          You are essentially correct!

                          A. Don’t think in terms of “least resistance” – that can lead you astray. Current will take any valid, complete path unless there is a shunt. When it has an option to take a path with (essentially) zero resistance, then all the current will flow through that path instead of alternate paths that have loads (resistance). So, that’s the case here. 100% of the current will flow through the branch with the closed switch instead of the path with the element.

                          B. Since the switch is open, all current will flow through the branch with the element.

                          C. Current will flow through both loads, in inverse proportion to the resistance of those loads.

                          Remember the formula for current? I = E/R

                          In other words, if R2 is twice as large as R1, then it will have half the current flow that R1 does.

                          And here’s where saying current follows the path of least resistance is flawed. R1 has the least resistance in the scenario I just proposed, but it does not get all of the current. It just gets more.

                          Let me know if you have any follow-up questions.

                          BONUS QUESTION: In Circuit A, if we did not have the light bulb in the circuit, what would this circuit configuration be depicting?

                          in reply to: Fundamentals – Module 3 Unit 5 Question 11. #15463
                          Susan Brown
                          Keymaster

                            These are good questions, and it’s great to get a handle on this. Here are three scenarios. When the electrons get to the point where there are two possible paths, what will they do? In other words, tell me for each scenario (A, B, and C) how much current will flow through the different branches. For example, will 100% of the current flow through one or the other, or will it divide up in some way?

                            Are you able to answer this yet, or are you still unsure?

                            in reply to: FINAL EXAM: QUESTION #7 #15458
                            Susan Brown
                            Keymaster

                              Correct – no current. If there’s no current flowing, even when we have some voltage present, that means there’s an ____ in the circuit (fill in the blank). (it’s good to be more specific than “bad”)

                              And, the measurements we give you tell you which side the ____ is on.

                              in reply to: Voltage drop and equivalent resistance #15456
                              Susan Brown
                              Keymaster

                                Voltage Drop:
                                Look in Unit 8. In the text before you get to the video, we define voltage drop and show you how to calculate it. Do you see it there?

                                For Equivalent Resistance of parallel loads:
                                We cover this in the 3rd video of Unit 5, and in the text below that. If you don’t want to do the actual calculation, you can just tell us the rule of thumb, which we show you in that video.

                                Let me know if you have follow-up questions!

                                in reply to: FINAL EXAM: QUESTION #7 #15454
                                Susan Brown
                                Keymaster

                                  This is a normal household circuit, so 120vac. You’d have L1 on one side of the bulb, and N on the other side. The bulb is good, but no voltage drop. We do measure 120vac wrt N from one side of the bulb.

                                  Is current flowing?

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