Circuit to change the current and voltage of a dc circuit?

In summary, the conversation is discussing a question about a circuit that involves two port networks and voltage sources. The person asking for help is struggling with the circuit and is unsure about the purpose of the 0V terminals. They are also unsure if they have studied the relevant topics yet. The conversation also mentions the concepts of Thevenin and Norton. The question may be deliberately vague to test the students' problem-solving skills. The simplest circuit suggested is Vin through a voltage follower with a series resistor, R, to Vout. Some additional clarifications are given about the correct approach to answering the question.
  • #1
126
2
I wasn't sure whether to post this here or in the 'homework' section... technically it is not a homework question, but I will be happy to move it...

I am really struggling with this circuit:
upload_2015-1-25_14-16-29.png

:'(
At the moment, I have no clue what to do for part i). I am sure that I will get part ii) afterwards, but I just don't know how to change the pd and current, and I don't really understand the purpose of the 0V terminals..

Thank you in advance for any help!
 
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  • #2
This question seems to be context related.
It will be testing the coursework just done, so we need to know what that was and what questions came earlier.
 
  • #3
21joanna12 said:
I am really struggling with this circuit:

Have you been studying "two port" networks or was this question asked before that topic was mentioned ?

You could look at examples of two port networks that have voltage sources in them to get some ideas.
There are lots of notes about two port networks online. e.g. http://ocw.nthu.edu.tw/ocw/upload/12/237/05handout.pdf
 
  • #4
Have you studied Thevenin and Norton yet?

If so you know the answer already and just need the courage to risk making a mistake or two.

Always parse questions to break them into individual parts.
False starts are just experiments . You have to go down a lot of blind alleys to learn any neighbvorhood...

What's simplest two element circuit you can think of that containss a voltage(p.d.) and resistance ?
Now - if we take them at their word and give Iin a small constant value,
i think you can answer (i) with one component.

That should lead you into answer for (ii).
 
  • #5
This question comes from olympiad past papers, Page 3, so there is no history to help identify "very simple crcuit".
http://www.physics.ox.ac.uk/olympiad/Downloads/PastPapers/BPhO_Round_2_Paper_2012_Final.pdf

The question may be deliberately vague so as to see how students handle the challenge. The simplest circuit that I can see is Vin through a voltage follower with a series resistor, R, to Vout. There may be no right answer.
 
  • #6
Interesting set of questions.

Vin and Iin are irrelevant
(i) is a voltage source of Vout in series with r, or a current source of Vout/r in parallel with r.

(ii) is worded to trip up those who do not read carefully. It mixes constant current and voltage sources, to make it hard for beginners.
 

1. How can I change the current and voltage in a DC circuit?

To change the current and voltage in a DC circuit, you can use a variety of components such as resistors, capacitors, and inductors. These components are used to manipulate the flow of electrons and alter the electrical properties of the circuit.

2. What is the difference between current and voltage in a DC circuit?

Current refers to the flow of electric charge, measured in amperes (A), while voltage is the measure of the potential difference between two points in the circuit, measured in volts (V). In a DC circuit, current and voltage are directly proportional to each other, meaning that as one increases, the other will also increase.

3. How do I increase the current in a DC circuit?

To increase the current in a DC circuit, you can decrease the resistance by adding more conductive components, such as wires or larger batteries, or by increasing the voltage. This will allow more electrons to flow through the circuit, resulting in an increase in current.

4. Can I change the current and voltage in a DC circuit without altering the components?

Yes, you can change the current and voltage in a DC circuit without altering the components by using a device called a transformer. A transformer is a device that can increase or decrease the voltage and current in a circuit without changing the components.

5. What is the purpose of changing the current and voltage in a DC circuit?

The purpose of changing the current and voltage in a DC circuit is to control the amount of power being delivered to different components in the circuit. By altering the current and voltage, you can adjust the intensity and speed of electrical devices, making them more efficient and safer to use.

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