Susan Brown

[Susan Brown]

Hi Michael,
You assume correctly. Without voltage, there will be no current flow.

What two items are absolutely necessary for current flow to happen? (hint: you’ll need to be able to answer this on the final exam, so it’s good to make sure you know it now!)

[Susan Brown]

Hi Dylan,

See this video where we step through a similar calculation in more detail, and see if that helps. If not, you’ll need to show me your steps.

https://youtu.be/iHB3lxdc68E

[Susan Brown]

Hi Miguel,

Good question! I’ll give you a short answer here, because you’ll learn even more about AC power in the units ahead.

With DC, it’s easy to picture a battery with a positive and a negative pole or terminal, and how the electrons will flow in one direction if they have a complete circuit from one pole to the other. The terminals never change their charge.

In an AC circuit, the polarity of the power supply terminals switches constantly from positive to negative, causing the back and forth movement of the electrons.

Keep going through the next few units, and let us know if you need more details.

[Susan Brown]

Hi Richard,

Good question, and glad to see you are paying attention!

Part of the challenge in teaching Basic Electricity is that it is a pretty complex topic, and we’re only skimming the surface to equip appliance techs with enough knowledge to assist their troubleshooting, without diving so deep that it’s overwhelming.

When it comes to power transmission, remember that P = I x E. So, in that case, you can see that if you are given a fixed number for Power, increased voltage will result in decreased current.

But we also have the relationship of E = I x R, which shows voltage and current being directly proportional. In an appliance setting, if you are looking at an entire circuit, the value of E is usually fixed (either 120v or 240v). Thus, the variables tend to be I and R. However, as you will learn more about in Unit 8, we can also calculate the voltage drop across a particular load. The higher the current, the higher the voltage drop.

So, you not only have to understand the mathematical relationships between these electrical properties that Ohm’s Law is helping us to see, but the context that we’re using them in.

It takes some time and effort – but please keep working at it and asking us questions!

[Susan Brown]

Just to add to what Sam said…

Using a steamer to make sure you’ve removed all of the ice is one way to help make sure you won’t get a repeat of the problem.

Also, besides what Sam described, some models of fridges actually have a little cal rod heater that is used to prevent the freezing of the condensate drain.

I suspect that your resetting the timer or not was more of a coincidence, and didn’t really contribute to the fix.

[Susan Brown]

That’s correct!

[Susan Brown]

Hi Richard,
No apologies necessary! This is what we are here for.

Good question. There is a difference between the two diagrams. In Fig. 6-9 in the Kleinert book, there is a “series portion” and a “parallel portion”. The two loads in the series portion are in series with that whole parallel portion.

Here’s the diagram you’re talking about in the video:

The two loads that are in series, in the top circuit, are parallel to the other branches, not in series with them. Imagine electrons flowing back and forth from Line to N. In the Kleinert circuits, all of the electrons will have to travel through that series portion no matter which parallel circuit they also go through. In our set of circuits, that is not the case. Do you see the difference? If not, let me know, and we can continue to discuss. However – you’ll learn more about series and parallel circuits in the next unit as well, so that may be all you need.

[Susan Brown]

Okay – let us know if you do need further help on anything!

[Susan Brown]

I just emailed you

[Susan Brown]

You don’t have to earn Certification, but I don’t understand why you won’t let us help you understand this information more. I’ll email you about this later today.

[Susan Brown]

No worries!

[Susan Brown]

That’s correct! Good job.

[Susan Brown]

Hi Daniel,

Doing conversions can be a little confusing until you get some practice with them. Sometimes it helps to practice with something you are more familiar with first.

For example, think about meter, kilometer, and millimeter. These are items you can picture, and relate to.

A meter is about the same as 3 feet (a yard).
A kilometer is about the same as a half of a mile.
A millimeter is a tiny little length.

Kilo is 1000 of something
Milli is 1/1000 of something.

So, a kilometer is 1000 meters. (You could phrase this as “converting” 1 kilometer to meters, which gives you 1000 meters. 5 kilometers would be 5000 meters.)

A meter is 1000 millimeters.

Or, you could say the opposite. 1 millimeter is 1/1000 of a meter.

For example, if someone wanted you to convert 1 meter into kilometers, would you take 1 meter and multiply by 1000, or divide by 1000?

Answer that, and we’ll go from there.

[Susan Brown]

“Usually” is an important word! Here’s what we say in the unit

How long this valve is kept energized depends on the model, but it is usually kept on for 90 to 120 seconds.

So the best choice out of the possible answers we gave you is

Probably, but it depends on the model

[Susan Brown]

Hi Josh, welcome!
Any of the units that you have completed can be gone back over, including looking at the quiz results. That is an important way to study for your exams!

Let me know if you have any other questions.

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