# Homework Help: What chapters or subject i need to read in order

1. Jun 5, 2009

### transgalactic

what chapters or subject i need to read in charles A.desour BASIC CIRCUIT THEORY
order to solve the following question:

http://i40.tinypic.com/219rsyt.gif

2. Jun 5, 2009

### MATLABdude

You just need to know how to write up the basic differential equation. Doing this in the frequency domain (with a Laplace transform) might make it easier, however.

3. Jun 5, 2009

### transgalactic

i dont know how to get those differential equation.
i have this desour book
response to shock
what that mean??
i know that delta function is used for sampling a function
but thats too abstract
i know kirshgoff laws
i know differential equation

i cant figure out the middle part

if you know this book
then you can tell what chapter should i read foe this
??

4. Jun 6, 2009

### bitrex

Hi Transgalactic, here is how I'd go about solving the problem:

Using Kirchoff's current law, write down the first order linear differential equation describing the voltage across the capacitor when shunted by a resistor. Remember that the current from the generator equals the current through the capacitor plus the current through the resistor, and the equations for the current through a capacitor and resistor. After solving the differential equation, you'd have an equation describing the voltage across the capacitor as a function of time. Since Q = CV, if you have an equation describing the voltage across the capacitor as function of time you also have an equation describing the charge on the capacitor as a function of time. In this context I believe what they mean by a "shock input" is that the current goes from zero to some set value in zero time, i.e. the input is not steady state or some function of time like $$Asin(\omega t + \varphi)$$. Like MATLABdude said it may be easier to solve equations like this with Laplace transforms instead of grinding through the differential equation, but as I haven't studied them yet you're on your own..