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No- please answer the question I asked. If you don’t know the answer, just say so. I’m trying to step you through the thought process you need to go through to get to the correct answers
It is given clearly in unit 5. The rule of thumb, which is perhaps more important to know, is also shown on the third video. We also asked you a quiz question about it. Please look at that section of Unit 5, and let me know if something isn’t clear to you
Voltage drop occurs when current flows though a load.
The first question you need to ask yourself is: Do all 4 loads have current flowing through them, as the circuits are shown in the diagram? (With the detector switch closed) Please just answer that question for me
Hi Philip,
Yes, that is correct!
That is not correct, which is why I asked how you arrived at it. If I know what your thinking is, then I can see where your mistake is and help you better.
Do you think that the main coil is in series with some of the other loads? If so, then it would have to share the voltage drop with them. That would mean any loads it was in series with would not be able to drop 120vac.
Normally, to calculate voltage drop across loads in series, you would need to know the resistance of each load. Like you did in Question 4 on the midterm. But we don’t give you any resistances for Question 8, and we still say that you can give us a numerical answer for each voltage drop.
The key is accurately seeing the layout of the loads, given the state of the circuits as shown in the diagram.
A first question to ask yourself is: Do all of the loads receive current?
Let me know what you think.
and the booster is 30v
You mentioned the booster twice. Did you mean to say the main coil here?
What is your explanation for the 30vac?
By the way, if you watch that video I asked you to, he addresses the danger of thinking about “the path of least resistance.”
That’s the formula, and I can help you figure out how to use it correctly in a little bit. But first…
The rule of thumb is just putting into words what the equivalent resistance of parallel loads will be compared to the resistance values of the individual loads. Something like “the equivalent resistance will always be larger than the biggest load”. (that is not necessarily the answer – just an example)
This is arguably more important to know, because you can do quick evaluations of circuits using this rule of thumb that will help you as you’re analyzing a schematic.
First of all, what is the rule of thumb for equivalent resistance of parallel circuits? (It is explicitly stated in the video on equivalent resistance in Mod. 3, unit 5.)
Hi Josiah,
Yes – you have to score 90% or higher on EACH exam in the course. The Midterm is perhaps the most important one of all! It really pushes students to help them understand important electrical concepts. I’ll be grading yours soon and will email you.
Correct. The distance between each pulse (the “square waves”) will vary to do things like control the speed of a motor.
Be careful about that expression “path of least resistance”. If there is a path of NO resistance, such as a wire with a closed switch, then all of the current will flow through that instead of through a load. This is a “short”.
However, if there are two or more paths for current to flow, which all have loads, then some current will flow through all of them, not just the path with the least resistance.
I don’t know what the “120 volts” means at the end of your sentence – would you please explain?
Hi Angel,
“Constant duty cycle” means that the frequency of those square wave peaks are always the same. Does that make sense?
The big question is: DOES current flow through the main coil with the detector switch closed.
Hi Kelly,
We’re glad to help! Can you tell me which video (there are 3 in that unit) this is, and the timestamp for that section?
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