Superposition theorem (i've done what i believe is correct to work out current at each resistors but im not sure its correct)

[Scott92]

Hi is anyone any good with superposition as im not, i've done what i believe is correct to work out current at each resistors but im not sure its correct,
Thats my circuit ive got R1 at 0.9 R2 at 1.95 and R3at -1.05 Ive got to these numbers by doing E2 to short
4x2/4+2=1.33 I1=8/2+1.33=2.40 I2=2.40x4/(4+4)=1.2 I3=2.40x4/(4+4)=1.2
E1 to short I4=12/4+1.33=2.25 I5=2.25x2/(2+4)=0.75 I6=2.25x4/(2+4)=1.50
R1= I1-I6 R2=I3+I5 R3=I2-I4 Is this correct or am i miles away tried youtube videos but struggle find simple circuits on there.

 

[The Highlander]

Hi is anyone any good with superposition as im not, i've done what i believe is correct to work out current at each resistors but im not sure its correct,
View attachment 37167 Thats my circuit ive got R1 at 0.9 R2 at 1.95 and R3at -1.05 Ive got to these numbers by doing E2 to short
4x2/4+2=1.33 I1=8/2+1.33=2.40 I2=2.40x4/(4+4)=1.2 I3=2.40x4/(4+4)=1.2
E1 to short I4=12/4+1.33=2.25 I5=2.25x2/(2+4)=0.75 I6=2.25x4/(2+4)=1.50
R1= I1-I6 R2=I3+I5 R3=I2-I4 Is this correct or am i miles away tried youtube videos but struggle find simple circuits on there.

As a Physics teacher I would probably be giving you no marks at all for your efforts above even if the numbers were correct (which they don't appear to be!) because you have used absolutely NO units throughout, which means I have no idea whether the values you state are meant to be currents, voltages or resistances!

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I'm not about to spend time trying to decipher them either (because they don't appear to be right anyway) but I will show you the way you should be tackling this kind of problem (below)...

You start by 'removing' ('shorting') one of the power sources and calculating all the values in the circuit as if it simply wasn't there; this is best done in a table like this...

Ignoring E2	R1​	R2​	R3​	R2||R3​	R1 + R2||R3 {Totals]​
R​	2​	4​	4​	2​	4​	Ohms
E​	4​	2​	2​	4​	8​	Volts
I ​	2​	1​	1​	2​	2​	Amperes

Then you add those values onto an appropriate circuit diagram, thus...

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Then you repeat the procedure now 'removing' the other power source to get...

Ignoring E1	R3​	R2​	R1​	R2||R1​	R3 + R2||R1 {Totals]​
R​	4​	4​	2​	1⅓​	5⅓​	Ohms
E​	9​	1​	2​	3​	12​	Volts
I ​	2.25​	0.75​	1.5​	2.25​	2.25​	Amperes

and
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Now you can 'Sum' the values for current & voltage at each position on the original circuit like this...

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I have entered a couple of the final values for you to start you off but please make sure you replace all the question marks with your own answers before you look at my final solution to ensure that you know what you're doing. (If you don't get the same answers as me then come back and tell us what you got and the discrepancy will be explained for you.)

Spoiler: Do NOT open until you have entered values above!

Here is what the final circuit diagram should look like (and you can now read off it whatever quantity (current or voltage drop) the question asks you to determine at any point in the circuit...

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Hope that helps.

 

[Scott92]

Thats a fair better way of explaining it and i got them all correct once explained that way! So when asked my current through a resistor is just asking for this method basically. Can i ask why you used the term E for voltage or am i misreading that Thanks again

 

[The Highlander]

Thats a fair better way of explaining it and i got them all correct once explained that way! So when asked my current through a resistor is just asking for this method basically. Can i ask why you used the term E for voltage or am i misreading that Thanks again

E ≡ Electromotive force.

Ohms law is often written as: E = I × R

Voltage (or e.m.f.) is, after all, a Potential Energy (Joules per Coulomb of Electric Charge)

 

[Scott92]

Yes course bloody **** thanks again mate really appreciate it