Can somebody tell me the calaculations of this 2 transistor circuit?

In summary, the conversation discusses the calculations for a BJT circuit and the difficulty of finding the answers without being given them directly. It is suggested to label the voltages of each node and use the relationship between the different ports of a BJT to solve the problem. The base-emitter voltage of the 2N5401 Q6 is mentioned as being 0.62V when it begins to turn on, resulting in a constant current of 10mA through R9 and Q7. The importance of learning and understanding the process rather than just being given answers is emphasized.
  • #1
michael1978
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can somebody tell me this circuits calculations, how come 10mA
please
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  • #3
michael1978 said:
can somebody tell me this circuits calculations, how come 10mA
pleaseView attachment 218125 View attachment 218125 View attachment 218125
To start do you know how to solve for BJT circuits?
If you do know the relationship between the different ports of a BJT, then you can do what berkeman said and dive into the math.
 
  • #4
Just a short hint:
When you assume a "normal" (classical) value for the voltage across the B-E path of Q6 (linear operation of Q6), it is a very simple task to get a rough estimate for the current through a resistor which is in parallel to this B-E junctiun.
 
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  • #5
why you make it so difficult?
it easy, i put the problem in other forum
this is the answer for there
The base-emitter voltage of the 2N5401 Q6 is about 0.62V when it begins to turn on. When Q6 turns on it begins to cutoff Q7 so the current in R9 and Q7 is constant at 0.62V/62 ohms= 10mA.
 
  • #6
michael1978 said:
why you make it so difficult?
it easy, i put the problem in other forum
this is the answer for there
The base-emitter voltage of the 2N5401 Q6 is about 0.62V when it begins to turn on. When Q6 turns on it begins to cutoff Q7 so the current in R9 and Q7 is constant at 0.62V/62 ohms= 10mA.

The goal of this forum is to share knowledge and grow the community and members, not to just blindly give you answers. In order to properly help you learn we need to know what level of experience you have, and why you are stuck on a problem. We won't spoon feed you answers if you don't respond to our questions.
 
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  • #7
michael1978 said:
why you make it so difficult?
Why do you need to be given answers, when it is so easy to figure them out with our hints. You will not get very far in life with this approach, I'm afraid.

Thread is done.
 
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1. What is the purpose of this 2 transistor circuit?

The purpose of this 2 transistor circuit is to amplify and control electrical signals. Transistors are semiconductor devices that act as switches or amplifiers in electronic circuits.

2. How do I calculate the voltage gain of this 2 transistor circuit?

The voltage gain of a 2 transistor circuit can be calculated by dividing the output voltage by the input voltage. This can be found by using Ohm's Law (V=IR) and Kirchhoff's Current Law to analyze the circuit's components and determine how they affect the voltage.

3. What are the different types of 2 transistor circuits?

There are several types of 2 transistor circuits, including common emitter, common collector, and common base configurations. Each type has its own unique characteristics and uses in electronic circuits.

4. How do I determine the biasing of this 2 transistor circuit?

The biasing of a 2 transistor circuit can be determined by calculating the voltage and current at each transistor's base terminal. This will help determine if the transistors are functioning in the desired operating region.

5. Can you explain the function of each component in this 2 transistor circuit?

The function of each component in a 2 transistor circuit can vary depending on the specific circuit design. However, in general, the transistors act as amplifiers, capacitors store and release electrical energy, and resistors control the flow of current. It is important to analyze the circuit and understand how each component contributes to the overall function.

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