LOTS of Electrical Maths Problems

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Discussion Overview

The discussion revolves around various electrical mathematics problems related to amplifiers, operational amplifiers, and circuit analysis. Participants seek assistance with specific calculations and conceptual clarifications, particularly in preparation for an upcoming exam.

Discussion Character

  • Homework-related
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant requests help with multiple problems involving amplifier circuits, including calculations of voltage gain, current gain, and power gain.
  • Another participant questions the appropriateness of the original poster's approach, suggesting they should show their work instead of expecting direct answers.
  • A participant clarifies that their inquiries are not for homework but for exam preparation, indicating they have some answers but lack understanding of the methods.
  • There is a call for participants to explain their reasoning to facilitate better understanding and learning.
  • One participant expresses urgency for assistance due to an imminent exam.

Areas of Agreement / Disagreement

There is no consensus on the appropriateness of the original poster's requests, with some participants advocating for a more independent approach to learning while others are willing to provide help. The discussion remains unresolved regarding the best way to assist the original poster.

Contextual Notes

Participants have not provided detailed assumptions or specific methods used in their calculations, which may limit the clarity of the discussion.

Who May Find This Useful

Students preparing for exams in electrical engineering or related fields, particularly those struggling with amplifier circuits and operational amplifier concepts.

fcukniles
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I'm confused about quite a lot of this stuff i have numbered it so if you can help in any of them please post what number you are helping with!
thankyou.

1. Draw the equivalent circuit of an amplifier with an input resistance of 3 k, output
resistance 100 and unloaded voltage gain of 1000.

It is fed from a signal source which is a pressure transducer having a sensitivity of 1mV/Pa (1 Pa = 1 N/m2) and an output resistance of 1000. It drives a recorder having an input resistance of 500 and a full scale deflection of 2 V recorder input.

Calculate:

(i) the percentage recorder deflection when the pressure is 2 Pa [62.5%].

(ii) the following gains measured between the transducer and the recorder
terminals:

(a) voltage
(b) current, and
(c) power

2)6. You have two identical amplifiers, each having an open-circuit voltage gain of 100, an input resistance of 1k and an output resistance of 100. You propose to cascade them to produce a two-stage amplifier.

Draw the "black-box" equivalent circuit of the arrangement, including an ideal voltage source for the input and assuming an open-circuit output.
Calculate the overall voltage gain from the input of the first amp to the output of the second.

You now find that, in practice, your source has an internal resistance of 1k and the output load is 50
Draw the new "black-box" equivalent circuit of the arrangement, and calculate the new overall voltage gain from the input of the first amp to the output of the second.

If you didn't know better, you might think that the overall gain would be
100 x 100 = 10 000. Why is the actual gain only about one-third of this?

3)(a) Explain the principal characteristics of an operational amplifier.
(b) Compare the functions of an ‘inverting’ and ‘noninverting’ operational
amplifier.
(c) Briefly explained how a summing amplifier may be used as a digital to analogue converter.

4)
Draw the block diagrams of operational amplifiers suitable for performing the
following mathematical functions.

(a) vo = -5vin (b) vo = -(3v1 + 2v2)
(c) vo = 10v1 - v2 (d) vo = 6 v1 dt.

Thanks for any help...you guys are about 10000x more helpful than my teacher who says 'look in you book stop bothering me!' if only the book wasnt ****!
 
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fcukniles said:
Thanks for any help...you guys are about 10000x more helpful than my teacher who says 'look in you book stop bothering me!' if only the book wasnt ****!

You should listen to your teacher!

Show us what you've done (rather than expecting someone to do your homework for you) and wait for it to be moved to the Homework section.
 
this isn't homework, I've got a exam this week am just clearing up things i don't understand, i have got a list of answers just not sure how to come about them
 
i realize there is a lot there sorry but any help for them would be much apricated
thnx guys
 
got a exam tomorrow afternoon if anyone could help b4 then would be class thanks
 
You need to explain your reasoning nevertheless... we have no incentive to help if you do not explain your methods... and the reason is, a person just cannot learn from people if the person helping does not understand the student's weakness.
 

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