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Definition
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Calculating Resistors in series
Calculating Resistors in parallel |
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Definition
Requ = R1 + R2 + R3...
1/Requ = 1/R1 + 1/R2... |
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Definition
Rule 1) assume direction of current
Rule 2) Loop Rule: sum up all potential differences (ie Voltage) when going through the closed loop in a circuit = 0 |
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Capacitors in series
Capacitors in parallel
(Q=CV)
(W = 1/2CV^2) |
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Definition
1/Cequ = 1/C1 + 2/C2...
Cequ = C1 + C2... |
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| steps for RC circuit and equation |
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Definition
Step 1: figure out quatnity of interest (I,V,Q) when t=0
Step 2: figure out value at t=infinity
Step 3: connect by exponantial using RC as time constant
Q(t)= -CV e^(-t/RC) + CV
(Vcap(t)= 1/C Q(t) = Vbatt (1-e^(-t/RC)) |
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| a flash for a camera: C = 1200uf. what resistance is needed in the RC circuit if the flas is to charge to 90% of its full charge in 25 sec |
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Definition
Q(t) = Qfin (1-e^(-t/RC)
Q(t) Q(25)
---- = ---- = .9
Qfinal Qfin
.9 = 1-e^(-25/R1200)
ln(e^(-25/R1200) = ln (1-.9)
-25sec 25sec
------- = ln(.1) => R = - ------
RC 1200uf*ln(.1) |
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| formula for the magnitude of magnetic force |
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Definition
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| magnetic feild & work on charge |
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Definition
when F is perpendicular to v, no work
Fcentri = 1/r mv^2
mv
r= ----
qB |
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electric force
magnetic force
---> v=? |
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Definition
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