Simplify Circuit: Understand How I1+I2+U1 = Whole Circuit

[dontwannatellyou]

[ Mod Note: relocated to homework forum so template is missing ]

Hi
Iwas soving a problem and the question is to simplify the circuit . Ididnt understand how the whole circuit is the same as the sum of I1 and I2 and U1 (which is a voltage source ) and I3 and R1 don't play a role
Thank you

 

[NascentOxygen]

This is similar to some of our homework questions, so I'll move this to the homework forum.

Imagine there is an external load, represented by an additional resistor R (not shown) between A and B.

Looking at these sources (and their ghastly non-standard symbols) can you say how much current is leaving this circuit to flow into resistor R via the wire at A?

 

[dontwannatellyou]

true its equal to i1 + i2

 

[dontwannatellyou]

But I have a problem where its not clear

 

[NascentOxygen]

true its equal to i1 + i2

[We're not finished yet.]

So that's the current leaving at A and going into the top of the load resistor, R.

Next, what would be an expression for current leaving the lower end of R to reenter the circuit at point B?

 

[NascentOxygen]

But I have a problem where its not clear

What things have you explored in simplifying this next arrangement?

 

[CWatters]

Have you studied Kirchhoff's Current Law?

 

[dontwannatellyou]

[We're not finished yet.]

So that's the current leaving at A and going into the top of the load resistor, R.

Next, what would be an expression for current leaving the lower end of R to reenter the circuit at point B?

also I1 +I2

 

[NascentOxygen]

also I1 +I2

So what is the voltage across the load resistor, R?

◉ Now, as a learning exercise, deduce what must be the voltage across the top left current source (the source supplying I₁ ).