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tenshinoakuma) wrote2008-04-05 01:31 am
tenshinoakuma) wrote2008-04-05 01:31 am
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Uni brain dump for my own reference seeing as I always lose my notes.
Electrical Systems 100
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Electrical Systems 100
P = VI for Voltage/Current sources? P = I^2 R for resistors
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Super Mesh - remove current source and any elements connected in series (does it include voltage sources?). 2 equations formed. 1) mesh analysis (2 current loops I1 and I2 present in the overall loop) 2) if source is up, I1 up and I2 down, then source value = I1 - I2.
NODAL ANALYSIS - node = juction of 2 or more branches. With application of KCL, 1) assign currents entering -ve = currents leaving +ve 2) all currents leave node = 0 (note directions may be messy as a result).
Super Node - formed by enclosing voltage between 2 non-reference (non-ground) nodes. Equation formed by analysing super node and any branches coming from the super node as is in nodal analysis (KCL). Use KVL on super node for 2nd equation (resistors have polarity with respects to the ground point?)
Super Positioning - SC/OC one V source/I source at a time and solve mesh equation for resultant circuit. If there are two sources, will need to solve 2 times. CANNOT SC/OC dependent sources. For the value of I you want to find, add respective I values of each mesh equation. NOT applicable to power. Note: VERY LITTLE POINT IN DOING THIS (just do a normal mesh analysis instead)
Thevenin's Theorem - 2steps to obtain Thevenin Equivalent Circuit containing V(Th), R(Th) and R(L) (or other varying circuit bit you want to measure) where R(L) is the resistance measured(?) at terminals a-b
Step 1 Obtaining V(Th): Open circuit R(L) and measure voltage at a-b (= V(Th)).
Step 2 Obtaining R(Th): Method 1 (no dependent sources) OC/SC sources, OC R(L) and find total resistance. Method 2 (dependent sources) OC/SC independent sources, OC R(L) and apply either V/I source (known as Vt/It) at a-b, measuring either It/Vt respectively. R(Th) = Vt/It (therefore rearrange equations until Vt is in terms of It or vice versa).
(What's the point of adding the test voltage? What are we trying to find? I through a-b?
Norton's Theorem - EASY WAY TO DO THIS? Find Thevenin's and then CONVERT. "Proper" way to do this. Norton Equivalent Circuit contains I(N), R(N) (=R(Th)) and whatever circuit bit you want to measure between terminals a-b.
Step 1 Obtaining I(N): Remove portion of network Norton's equiv needs to be found. SC a-b and find I(N).
Step 2 Obtaining R(N): SAME AS OBTAINING R(Th).
Step 3: ???
Step 4: Profit
Max Power Transfer Theorem - (VTh/(RTh + RL))^2 * RL i.e V^2/4R^2
-
Super Mesh - remove current source and any elements connected in series (does it include voltage sources?). 2 equations formed. 1) mesh analysis (2 current loops I1 and I2 present in the overall loop) 2) if source is up, I1 up and I2 down, then source value = I1 - I2.
NODAL ANALYSIS - node = juction of 2 or more branches. With application of KCL, 1) assign currents entering -ve = currents leaving +ve 2) all currents leave node = 0 (note directions may be messy as a result).
Super Node - formed by enclosing voltage between 2 non-reference (non-ground) nodes. Equation formed by analysing super node and any branches coming from the super node as is in nodal analysis (KCL). Use KVL on super node for 2nd equation (resistors have polarity with respects to the ground point?)
Super Positioning - SC/OC one V source/I source at a time and solve mesh equation for resultant circuit. If there are two sources, will need to solve 2 times. CANNOT SC/OC dependent sources. For the value of I you want to find, add respective I values of each mesh equation. NOT applicable to power. Note: VERY LITTLE POINT IN DOING THIS (just do a normal mesh analysis instead)
Thevenin's Theorem - 2steps to obtain Thevenin Equivalent Circuit containing V(Th), R(Th) and R(L) (or other varying circuit bit you want to measure) where R(L) is the resistance measured(?) at terminals a-b
Step 1 Obtaining V(Th): Open circuit R(L) and measure voltage at a-b (= V(Th)).
Step 2 Obtaining R(Th): Method 1 (no dependent sources) OC/SC sources, OC R(L) and find total resistance. Method 2 (dependent sources) OC/SC independent sources, OC R(L) and apply either V/I source (known as Vt/It) at a-b, measuring either It/Vt respectively. R(Th) = Vt/It (therefore rearrange equations until Vt is in terms of It or vice versa).
(What's the point of adding the test voltage? What are we trying to find? I through a-b?
Norton's Theorem - EASY WAY TO DO THIS? Find Thevenin's and then CONVERT. "Proper" way to do this. Norton Equivalent Circuit contains I(N), R(N) (=R(Th)) and whatever circuit bit you want to measure between terminals a-b.
Step 1 Obtaining I(N): Remove portion of network Norton's equiv needs to be found. SC a-b and find I(N).
Step 2 Obtaining R(N): SAME AS OBTAINING R(Th).
Step 3: ???
Step 4: Profit
Max Power Transfer Theorem - (VTh/(RTh + RL))^2 * RL i.e V^2/4R^2
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