전력 기술자 시험 문제 및 주요 개념

### 전력 기술자 자격증을 위한 주요 시험 문제: 인사이트와 전략
* 🔌 전력과 송건웅 강사는 **전력기술사 자격증의 기출문제는 지난 8년간의 실제 시험 데이터**를 바탕으로 출제되기 때문에 자주 출제되는 문제를 숙지하는 것이 중요하다고 강조합니다.
* 📊 첫 번째 문제는 상대적 유전율에 관한 것으로 **2017년부터 9번 출제**되었으며, 특히 무극성 특성과 뛰어난 가성비로 인해 **세라믹 커패시터를 정답**으로 선정한 **티타늄 산화물을 유전체로 사용하는 커패시터**에 초점을 맞춰 출제되었습니다.
* ⚡ 전해 커패시터는 극성이 있어 적용하기 어렵고 마일라 커패시터는 필터에 사용되는 것으로 유명하지만, **티타늄 산화물과 무극성**이라는 핵심 사항을 고려할 때 **세라믹 커패시터가 적합**하다는 결론에 도달하게 됩니다.
* 🔍 2017년부터 6번 출제된 두 번째 문제는 직렬 연결과 병렬 연결의 등가 저항에 대한 이해를 묻는 문제로, **5옴 저항 5개가 직렬로 25옴, 병렬로 1옴**을 만들어 직렬 저항이 **25배 더 커지는 문제**입니다.
* 병렬 연결에 대한 계산 방법이 강조되어 있으며, 동일한 저항에 대해서는 **R/n 공식을 사용**하여 프로세스를 간소화하고 다른 값에 대해서는 표준 접근 방식이 필요합니다.
* 2018년부터 8번 출제된 세 번째 문제는 강자성 물질에 대한 지식을 테스트하는 문제로, **철, 니켈, 망간**을 예로 들며 **백금은 반자성**으로 분류되어 암기 기술의 중요성을 강조합니다.
* 📚 전반적으로 이 세션은 참가자들이 논의된 질문에 대해 생각해보고 향후 성공을 위해 자료를 내재화하도록 장려하며, **다음 세션에서 더 가치 있는 내용**을 약속합니다.

송건웅 강사는 효과적인 준비를 위해 자주 출제되는 전력기술사 시험 문제를 숙지하는 것이 중요하다고 강조합니다.

Hello everyone, I am Song Geon-woong from the Electric Power Department. Continuing from our last session, I would like to discuss the exam questions that have been asked five or more times over the past eight years for the Electric Power Technician certification. As I mentioned last time, the content I bring is based on actual questions that have appeared in the exams, checked against data on how many times they have been asked. Therefore, you can study these questions with confidence regarding their reliability. Please remember that you must be familiar with these questions.

Today, we will dive into Part 2. The first question I have brought is one that has appeared nine times. It started in 2017 and has been asked a total of nine times up to 2023. The question is about relative permittivity.

I would like to talk about the types of capacitors that use titanium oxide as a dielectric, which are non-polar and have excellent performance for their price, making them widely used. Here, we should focus on a couple of key points. First, titanium oxide has been mentioned. Second, it is non-polar. If we keep these two points in mind, we can immediately identify that we are referring to ceramic capacitors. 

On the other hand, electrolytic capacitors, unfortunately, are polar. Because they are polar, they do not apply to this topic. Next, there are mylar capacitors, which are somewhat similar to ceramic capacitors; however, they are also used in applications like bypass filters or other types of filters. The same goes for ceramic capacitors. But when we come across keywords like titanium oxide, non-polar, and good cost-performance ratio, we can confidently conclude that we are indeed talking about ceramic capacitors.

Next, we have the mica capacitor. This type has good high-frequency characteristics and is primarily used in filter circuits. Since the topics of tantalum or non-polarized capacitors and cost-effectiveness are not relevant here, you can opt for ceramic capacitors. Of course, non-polarized capacitors are uniform, but due to the other conditions, you need to choose ceramic capacitors. So, what should you summarize from this issue? What do you need to clarify? You can just take this with you. In your problems, if you come across tantalum and it is non-polarized and cost-effective, you should not hesitate to choose ceramic capacitors. Then, expanding a little further, if a film capacitor comes up, remember that it has the characteristic of being non-polarized. If you are asked what types of non-polarized capacitors there are, the answer would be film capacitors.

If you provide a capacitor, that would be great. So, this problem is that the ceramic capacitor is the correct answer, and since it has been asked a total of nine times, I hope you will definitely take this problem with you. Now, let's take a look at the second question of today. This question has been asked about six times, starting from the fourth round in 2017 up to the second round in 2023. Let me read the question for you. Such questions come up quite often and can be unexpectedly tricky. So, I will help you to clearly understand this question. 

When five resistors of equal value are connected in series, what is the equivalent resistance? The question is asking how many times the equivalent resistance in series is compared to the equivalent resistance when connected in parallel. In other words, it is asking whether you can distinguish between the situation when five resistors are connected in series and when they are connected in parallel.

So, if you do it once, you can try it. I will connect five resistors in series. So, R in series, we are trying five resistors. Then, this is how it looks: one, two, three, four, five resistors are connected. Now, it means we need to combine them into one, as it's a combined resistance. So, we can express it as one. But how many ohms is one resistor? It’s said to be 5 ohms. Let's write that down. 

Now, if you connect five 5-ohm resistors in series, you can simply add them up since they are in series. So, it becomes 25 ohms. Therefore, when resistors are connected in series, the total resistance is 25 ohms. Did you catch that? Next, let's look at parallel connections. So, it's connected like this: one, two, three, four, five, connected in parallel, and we need to combine them into one.

Let's combine this. So, this is also a series of five-ohm resistors connected together. Now, how should we calculate this? There are two methods: one is to use a formula, and the other is to use a standard approach. The standard approach is to add them up when they are connected in parallel: 1/5 + 1/5 + 1/5 + 1/5 + 1/5. This gives us the correct calculation. However, when the same resistance is connected in parallel multiple times, we have a formula for that, which is R/n. Here, n refers to how many are connected in parallel. So, what is the value of n? It's five, right? And the exact value of one is five ohms. Since we have five of them in parallel, we calculate it as 5 divided by 5, which equals 1. So, when we calculate this, we find that it results in 1 ohm.

According to a certain formula, the combined resistance formula is represented as r over n. However, this applies when multiple resistors of the same value are connected. If the resistor values are different—let's say one is 593 ohms and the other is 1 ohm—then we have to approach it using the standard method I showed earlier. 

Now, we have solved the problem. Let's compare the results. Here, we see that when connected in series, the resistance is 25 ohms, while in parallel, it's significantly different. How many times greater is it? When we multiply, we find it's 25 times greater, right? Therefore, the combined resistance in series is 25 times that of the combined resistance in parallel. So, the correct answer is option 1. 

Some of you might find this confusing when you first encounter the problem, but that's not unusual. It's perfectly normal to be confused because comparing two different setups in electricity can be quite challenging.

For those who are encountering this for the first time or are non-majors starting from scratch, it can feel quite awkward and heavy, which is completely understandable. However, since we've worked through it together, you can definitely make it your own. So, we can say it's 25 times, and while it has only been tested 6 times, this number could change, and it could have been tested more often. Therefore, this type has not just been tested 6 times but rather 10 or even more than 12 times. So, even if it's given as a 15-point question instead of a 5-point one, you should be able to solve it just fine. Now, we've looked at the second problem together, and we’re moving on to the last one. I've brought the third question, which has been tested 8 times, starting from the fourth test in 2018 up to the third test in 2023. Let me read the question: Which of the following is not a ferromagnetic material? Ah, I've heard this one quite a bit.

What are ferromagnetic materials? Ferromagnetic materials refer to substances that exhibit a significant degree of magnetization. Now, just take this: iron, nickel, cobalt, and manganese. Then there are paramagnetic materials. Paramagnetic materials are substances that are magnetized, although not to the same extent as ferromagnetic materials. You should know five examples: platinum, oxygen, nitrogen, aluminum, and tin. Now, for diamagnetic materials, you can think of them as everything else that is not included in the previous categories. So, you don't need to memorize anything special about diamagnetic materials. You can simply remember that if it's not one of the two mentioned, then it is a diamagnetic material. Therefore, we don't need to memorize all three categories; just remember the first two. So, ferromagnetic materials include iron, nickel, and manganese.

If we change the order of the mnemonic, we have Nico Cheolmang, which means Nico got caught in the iron mesh. There is a mnemonic technique for this. Anyway, you can remember it as either Cheol Nico or Nico Cheolmang. It might be a bit embarrassing, but if you can memorize this, you can do everything. So what do we say? Nico Cheolmang. Ah, Nico Cheolmang got caught. We're going with Nico Cheolmang. And this is just to remember Baeksanji. Let's go with 137R, 137 Alju, Baeksanji. What was Baek Jong-won's way of speaking? He speaks with that Alju accent, right? So, thinking of Baek Jong-won, we remember Baeksanji like this. That's how we do it. Baeksanji Alju. Next, for the paramagnetic substance, you just need to consider the remaining elements, not the first two. So, for the lecture, we are not talking about the paramagnetic substance. Since it's Nico Cheolmang, it’s not platinum. Platinum is a diamagnetic substance.

We are now facing a problem, but in reality, we have memorized everything, so whether it's a strong magnetic body, a box magnetic body, or a weak magnetic body, we can solve them all. This is because we know about nickel-copper alloys and the Baeksan system. So, I hope you can take just this much with you. Today, we discussed the written exam questions for the regular technician certification that have been asked more than five times in the past eight years. How did you find today's session? The first question and the third question were somewhat memorization-based, while the second question involved a rather tricky problem related to the resistance values in series or parallel connections and comparing them. I hope you will reflect on these problems once more and internalize them. I have prepared three questions for you today.

In the next video, I will bring you better and more useful content. Thank you for today as well.

반드시 나올 수밖에 없는 문제 - 전기기능사 필기

전기는빠지직(송건웅)

전력 기술자 자격증의 주요 시험 문제

이 토론에서는 지난 8년 동안 5회 이상 출제된 전력 기술자 자격증 시험 문제, 특히 전기 기술자 자격증 시험 문제에 초점을 맞춥니다.

첫 번째 문제인 상대 유전율에 관한 문제는 2017년부터 9번 출제되었으며, 산화티타늄을 유전체로 사용하는 커패시터와 관련이 있습니다.

핵심은 산화티타늄의 무극성 특성과 비용 효율성이며, 세라믹 커패시터가 정답이라는 결론으로 이어집니다.

이 문제에는 동일한 값의 저항기 5개를 직렬 및 병렬로 연결해야 합니다.

직렬로 연결된 경우 총 저항은 25옴(각각 5옴)입니다.

병렬로 연결하면 등가 저항은 1옴으로, R/n 공식을 사용하여 계산되며 여기서 n은 저항의 수입니다.

결합 저항 공식은 여러 저항의 값이 같지만 값이 다른 경우 표준 방법이 필요한 경우에 적용됩니다.

이 경우 직렬 저항은 25옴이고 병렬 저항은 훨씬 낮아져 직렬 저항이 25배 더 커집니다.

이 문제는 특히 초보자에게는 혼란스러울 수 있지만 연습하면 이해하기 쉬워집니다.

강자성, 상자성, 반자성 재료의 이해

철, 니켈, 코발트, 망간과 같은 강자성 물질은 상당한 자화 현상을 보입니다.

백금, 산소, 질소, 알루미늄, 주석과 같은 상자성 물질은 자화 정도가 덜합니다.

상자성 물질은 앞의 두 범주에 속하지 않는 모든 물질을 포함하며, 나머지 원소가 이에 해당합니다.

자성체 및 기술자 자격증 마스터하기

니켈-구리 합금과 백산계에 대한 이해를 바탕으로 강자성체, 상자성체, 약자성체와 관련된 문제를 해결할 수 있는 지식을 갖추었습니다.

오늘 세션에서는 저항값 암기와 문제 해결의 중요성을 강조하기 위해 정규 기술사 자격증의 과거 필기 시험 문제를 중심으로 진행되었습니다.

다음 영상에서는 더 나은 내용을 약속하며 청중을 위해 세 가지 문제를 준비했습니다.