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!(adsbygoogle = window.adsbygoogle || []).push({});

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 ****!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# LOTS of Electrical Maths Problems

**Physics Forums | Science Articles, Homework Help, Discussion**