Introduction.
Nice to meet you!
I am Fai, a new engineer in 2017.
I am almost a beginner in regards to electrical circuits, as I had a mechanical background in college.
In this blog, I would like to share with you
my own understanding of the why and how about electrical and electronic circuits that I have questions about in my daily work.
Thank you for your cooperation.
This time, I would like to introduce a question I had during the technical training.
First of all, we studied about "parts" during the technical training.
Parts are mainly classified into two types: "passive parts" and "active parts".
Then I thought to myself, "Why bother with 'passive parts'?
Why do we have to go to the trouble of dividing them into passive and active parts?
Types of Parts
Have you ever seen the following?
Figure 1: Parts of an electronic circuit
These are the components of an electronic circuit, which can be divided into "passive components" and "active components" based on their operations.
By the way, these components can be divided into the following categories as illustrated in Figure 2.
Figure 2: Classification of Passive and Active Components
Next, the respective operations of passive and active components are explained.
Passive Components
Passive components are components that receive, consume, and dissipate energy from the outside.
Typical examples include resistors, capacitors, and coils.
For example, a resistor consumes power and limits the current to a certain level when voltage is applied from the outside, as shown in the figure below.
Figure 3: Resistor Function
In this way, a resistor has the function of receiving power from the outside and consuming it to limit the current.
About Active Components
Active components are components that can amplify and rectify energy provided from the outside.
Examples include bipolar transistors, FETs, and integrated circuits ( ICs ).
For example, a bipolar transistor allows a current between the collector and the emitter that is equal to the current in the base multiplied by hfe, as shown in Figure 4.
Figure 4: Bipolar transistor ( In this case, hfe is 100. )
Figure 4: How a bipolar transistor works
In this way, the bipolar transistor can amplify the current by itself.
Comparing the two schematics
Knowing the above two features, I formed the following impression.
Active components: "the 'leading role'" that actively moves electricity
Passive components: "the 'supporting role'" that just receives and flows electricity
However, when I compare the two circuits, I notice that they both contain passive components.
As you can see, a circuit cannot be built with active components alone, and passive components (resistors) play an important role in conducting current.
Also, although I thought that passive components played a supporting role, I now understand that they actually play an important role!
I will explain the crucial role in the next issue.
Conclusion
We have learned that each part can be divided into "passive parts" and "active parts" based on the differences in their actions.
I also learned that active components shine only when they are supported by passive components.
From now on, I would like to play an important role like passive components in my company and shine like active components.
Thank you for reading until the end!
Please look forward to the next issue!
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