Unraveling the Mystery of Transistors

• CalcYouLater
In summary, a diode is used to protect the base-emitter junction in a transistor, and the pnp transistor will have the same properties as the npn transistor if the added diode is reflected across the base lead axis.
CalcYouLater

Homework Statement

The base-emitter voltage, V_be, typically never exceeds .6V. Because of this low value, the base-emitter junction must be protected against too high a reverse voltage. A diode is usually used to protect the junction as shown in the figure for a npn transistor.

a. Explain the function of the diode and the conditions under which protection is given.
b. Draw the equivalent circuit for a pnp transistor.

The Attempt at a Solution

Sorry about the drawing. I am having trouble drawing straight lines with the circuit drawing software I am currently using.

I have no idea what a transistor does and why. I read various online material about the transistor before our lecture on the circuit element (I didn't have my textbook with me). The lecture seemed easy to understand, but I still have no insight as to exactly what a transistor does in the circuit configuration shown in the picture. I have also had 1 lab session dealing with the transistor in an emitter follower circuit. I asked the TA many questions about the circuit, but I could not get a clear understanding as to what the transistor does, or why it behaves the way it does. After the lab, I read the chapter on the transistor, but found it to be vague.

What is a transistor? What does the transistor do? What is a "collector"? What is an "emitter"? What is the "base"?

I realize that this is an extremely important circuit element, but from the little I know, it seems to have no function. I know that it certainly does have a function, but I am so lost in trying to understand it.

I am not worried about answering the above question. I want to first understand the transistor. I apologize if this is posted in the incorrect section.

If someone could either explain, or point me in the direction of resources that explain the transistor, it would be greatly appreciated.

Attachments

• Transistor.jpg
6 KB · Views: 480
Last edited:
If there were a reverse voltage applied to the circuit, would the diode need to be there in order to prevent the forward bias diode in the transistor from breaking down?

Last edited:
The more I think about it, the more it seems obvious. The diode prevents the forward bias diode in the p-n junction (emitter base junction) from taking damage. Protection is given as soon as the reverse voltage is greater than the voltage drop of the added diode (.6V). If that is true, then of course the pnp transistor will have the same properties. The difference being that the added diode would be reflected across base lead axis.

1. What are transistors and how do they work?

Transistors are electronic devices that act as switches or amplifiers. They are made of semiconductor materials, such as silicon, and have three layers: the emitter, base, and collector. By controlling the flow of electrons through these layers, transistors can amplify or switch electronic signals.

2. Why are transistors important in modern technology?

Transistors are the building blocks of modern electronics and have revolutionized the way we interact with technology. They are essential in devices such as computers, smartphones, and televisions, allowing for faster and more efficient processing of electronic signals. Without transistors, many of the technologies we rely on today would not be possible.

3. How were transistors invented?

Transistors were first invented in 1947 by scientists John Bardeen, William Shockley, and Walter Brattain at Bell Laboratories. They were trying to find a replacement for bulky and unreliable vacuum tubes, which were used in early computers. Their invention of the transistor paved the way for the development of smaller, more reliable, and more efficient electronic devices.

4. What is the future of transistors?

The future of transistors is constantly evolving as technology advances. Currently, researchers are working on developing transistors that are even smaller and more powerful, using new materials such as graphene and carbon nanotubes. These advancements could lead to faster and more efficient electronic devices.

5. How do transistors impact everyday life?

Transistors have a huge impact on everyday life, as they are used in a wide range of electronic devices that we use daily. For example, they are used in smartphones, laptops, televisions, and even in cars. They make these devices smaller, faster, and more efficient, making our lives easier and more connected.

Replies
4
Views
1K
Replies
59
Views
4K
Replies
11
Views
2K
Replies
10
Views
5K
Replies
5
Views
2K
Replies
2
Views
1K
Replies
13
Views
2K
Replies
4
Views
2K
Replies
68
Views
4K
Replies
4
Views
2K