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# calculus question help watch

1. I was given this assignment last week and I have around two weeks to complete this question but I do not know where to start, I'd be really grateful if someone could point me in the right direction. This is the question:

Your colleague tells you that the operation of a smoothing capacitor depends on its charging and discharging characteristics and these are what you should investigate. They show the results of a simple experiment in which a capacitor was connected in series with a resistor and then charged up from a DC supply. The voltage across the capacitor was measured and displayed by an oscilloscope and then compared with figures derive by calculation.

Here is the information about the circuit.

capacitor= 100nF

Resistor= 47KΩ

supply voltage= 5v

Charging characteristic for a series capacitive circuit:

v=V(1-e^-(t/T)) where T=CR and is called time constant

1. investigate what the other terms in the expression mean.

2. Calculate the time constant for the circuit.

3. plot the charging curve over the range 0 to 20ms

4. Investigate the meaning of 'time constant' from your graph and estimate a value.

5.Differentiate the charging equation and find the rate of change of voltage at 6ms.

6.from your graph measure the gradient at 6ms and compare this with the calculated value.
2. (Original post by simon 2538)
I was given this assignment last week and I have around two weeks to complete this question but I do not know where to start, I'd be really grateful if someone could point me in the right direction. This is the question:

Your colleague tells you that the operation of a smoothing capacitor depends on its charging and discharging characteristics and these are what you should investigate. They show the results of a simple experiment in which a capacitor was connected in series with a resistor and then charged up from a DC supply. The voltage across the capacitor was measured and displayed by an oscilloscope and then compared with figures derive by calculation.

Here is the information about the circuit.

capacitor= 100nF

Resistor= 47KΩ

supply voltage= 5v

Charging characteristic for a series capacitive circuit:

v=V(1-e^-(t/T)) where T=CR and is called time constant

1. investigate what the other terms in the expression mean.

2. Calculate the time constant for the circuit.

3. plot the charging curve over the range 0 to 20ms

4. Investigate the meaning of 'time constant' from your graph and estimate a value.

5.Differentiate the charging equation and find the rate of change of voltage at 6ms.

6.from your graph measure the gradient at 6ms and compare this with the calculated value.
I'd personally start with question 1. But in all seriousness, please may you outline what you're stuck with. This might also be better in the physics section.

1 and 2 are extremely easy, if you read the question and have some knowledge about symbols. 3 is an exponential plot, which shouldn't be too hard for you if you have knowledge about exponentials. 4 is using the principle of the time constant, which you have to explain, again relatively straight forward. Again with maths knowledge 5 should be alright, and hopefully you can do 6.

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3. (Original post by simon 2538)
I was given this assignment last week and I have around two weeks to complete this question but I do not know where to start, I'd be really grateful if someone could point me in the right direction. This is the question:

Your colleague tells you that the operation of a smoothing capacitor depends on its charging and discharging characteristics and these are what you should investigate. They show the results of a simple experiment in which a capacitor was connected in series with a resistor and then charged up from a DC supply. The voltage across the capacitor was measured and displayed by an oscilloscope and then compared with figures derive by calculation.

Here is the information about the circuit.

capacitor= 100nF

Resistor= 47KΩ

supply voltage= 5v

Charging characteristic for a series capacitive circuit:

v=V(1-e^-(t/T)) where T=CR and is called time constant

1. investigate what the other terms in the expression mean.

2. Calculate the time constant for the circuit.

3. plot the charging curve over the range 0 to 20ms

4. Investigate the meaning of 'time constant' from your graph and estimate a value.

5.Differentiate the charging equation and find the rate of change of voltage at 6ms.

6.from your graph measure the gradient at 6ms and compare this with the calculated value.
Someone else must be on the same course as you

http://www.thestudentroom.co.uk/show....php?t=3098301

To be honest a lot of this question is just plugging in the numbers they have given you to calculate other values, or plugging in several values over a range so that you get a set of points you can plot on a graph.
4. (Original post by simon 2538)
Your colleague tells you that the operation of a smoothing capacitor depends on its charging and discharging characteristics and these are what you should investigate.
I mean, really. The assignment asks you to investigate something on the pretext that your colleague has asked you to investigate it? Question-writers should be much more inventive, or much less: you should be "defusing a bomb by calculating the discharge", or else you should be "answering questions on this assignment".

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Updated: January 25, 2015
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