Simple question about KVL Equation in a BJT Circuit

In summary, The KVL equation for a BJT to find Ib is Vcc - IcRc - IbRb - Vbe = 0. The relationship between Ib and Ic is that they are equal to the emitter current. The drop across Rc should be calculated as IcRc.
  • #1
ryNze
2
0

Homework Statement



I am trying to find the KVL equation for this BJT in order to find Ib.
http://www.ece.auckland.ac.nz/oasis/a/att/qtatt/2028/2/261/IM010 [Broken]


Homework Equations





The Attempt at a Solution



My current equation looks like this.
Vcc - IcRc - IbRb - Vbe = 0

I am not entirely sure if this is correct.
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
1. Is the drop across Rc really just IcRc? (Hint: you're close, but no cigars).
2. More importantly, what is the relationship between Ib and Ic for a BJT?
 
  • #3
rude man said:
1. Is the drop across Rc really just IcRc? (Hint: you're close, but no cigars).
2. More importantly, what is the relationship between Ib and Ic for a BJT?

I just thought about it.
The base current and collector current equals to the emitter current.

So, the drop across the Rc is actually IeRc?
 
  • #4
Yes. Add the IbRc term to your original equation, don't use Ie.

Now for part 2?
 
  • #5
Can someone confirm or correct me?

Yes, your KVL equation looks correct. In a BJT circuit, the KVL equation is typically written as Vcc - IcRc - IbRb - Vbe = 0, where Vcc is the supply voltage, Ic is the collector current, Rc is the collector resistor, Ib is the base current, Rb is the base resistor, and Vbe is the base-emitter voltage. This equation follows Kirchhoff's Voltage Law, which states that the sum of all voltages around a closed loop in a circuit must equal zero. In this case, the closed loop is formed by the supply voltage, the collector resistor, the base resistor, and the base-emitter voltage. By solving for Ib, you can then use Ohm's Law to find the value of the base resistor. I hope this helps clarify the KVL equation for you. Good luck with your homework!
 

1. How does the KVL equation apply to a BJT circuit?

The Kirchhoff's Voltage Law (KVL) states that the sum of all voltages around a closed loop in a circuit must equal to zero. This law applies to BJT circuits as the voltage drop across the base-emitter junction and collector-emitter junction must be equal to the supply voltage. This allows us to analyze the circuit and calculate the unknown voltages using the KVL equation.

2. What is the significance of the KVL equation in a BJT circuit?

The KVL equation is significant in BJT circuits as it helps us to understand the relationships between different voltages in the circuit. It also allows us to calculate the unknown voltages and ensure that the circuit is properly designed and functioning correctly.

3. Can the KVL equation be applied to any BJT circuit?

Yes, the KVL equation can be applied to any BJT circuit, regardless of its complexity. As long as the circuit is a closed loop and follows the basic principles of Kirchhoff's laws, the KVL equation can be used to analyze the circuit and calculate the unknown voltages.

4. How do we use the KVL equation to solve a BJT circuit?

To solve a BJT circuit using the KVL equation, we must first identify all the voltages in the circuit and assign them with a polarity. Then, we can write the KVL equation by summing up all the voltages around a closed loop and setting it equal to zero. Finally, we can solve for the unknown voltages using algebraic manipulation.

5. Are there any limitations to the KVL equation in BJT circuits?

One limitation of the KVL equation in BJT circuits is that it assumes the components in the circuit are ideal. In reality, there may be some variations and imperfections in the components, which can affect the accuracy of the calculated voltages. Additionally, the KVL equation does not take into account any non-linearities in the circuit, which may be present in some BJT circuits.

Similar threads

  • Engineering and Comp Sci Homework Help
Replies
4
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
8
Views
974
  • Engineering and Comp Sci Homework Help
Replies
2
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
2K
  • Electrical Engineering
Replies
3
Views
691
  • Engineering and Comp Sci Homework Help
Replies
1
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
2
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
4
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
34
Views
5K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
1K
Back
Top