# Help Again!!! pleaseeeeeee

Discussion in 'Homework Help' started by ACDChelo, Sep 24, 2007.

1. ### ACDChelo Thread Starter New Member

Sep 24, 2007
2
0
I dont understand this either. I am new to electronics and cant understand this, can somebody please break this down in to english for me

A:determine the value for RL
B:Calculate the max power that could be delivered to RLif it were changed to that value
c:find the power delivered to RL if RL= 4ohm.

thanks please be in detail so i mite actually understand

2. ### hgmjr Moderator

Jan 28, 2005
9,030
214
Part A of this question seems to be already given. It looks like RL is labeled as 4 (ohms ?). The image is a bit blurry.

hgmjr

3. ### niftydog Active Member

Jun 13, 2007
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That text looks very familiar, what book is this from?

4. ### cumesoftware Senior Member

Apr 27, 2007
1,330
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The question A is quite incomplete. Although the resistor is said to have 4Ohm (in blue, looks like a solution), how to determine it without knowing the current that the circuit draws or it's equivalent resistance?
Question B: RLif? (don't know the concept)
Question C: Simple. (W = V x I and R = V / I - there is a third equation that saves you the trouble of calculating I)

5. ### recca02 Senior Member

Apr 2, 2007
1,211
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i think the question asks to determine RL for max power transfer,
second question follows requring to find the power at this load,
third requires to find power if Rl was to be 4 ohms,
in that case,
solve for equivalent circuit and find out the total resistance with the load resistance disconnected.
for max power transfer load impedance (resistance in this case) shud match (actually it shud be a conjugate of the impedance) the eq resistance of circuit.
now calculate the power the circuit takes from the source by using power=sq(i)(req+rl)=2sq(i)RL.
power delivered to load is sq(i)RL
of course u'll have to calculate i but that is easy since RL and Req are in series.
in above power eq use value of 4 ohms instead of Req for RL to get the third answer.

Jan 28, 2005
9,030
214