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 dont play a role
Thank you

 

MOD NOTE: Moved to Homework Help from General Electronics Chat.

 

How is U1 playing a role?

What does it even mean to talk about the "sum" of two currents and a voltage? What is sum of 5 A and 8 V?

 

How is U1 playing a role?

What does it even mean to talk about the "sum" of two currents and a voltage? What is sum of 5 A and 8 V?

I meant the sum if Í1 and i2 if you are unsure you could see the image

 

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 dont play a role
Thank you

Hi,

Let me try to rephrase this and tell me if it sounds right...

"I was solving a problem and the question is to simplify the circuit . I didnt understand how the whole circuit is the same as the sum of I1 and I2. U1 (which is a voltage source ), I3, and R1 dont play a role."

Does this sound right?

 

Hi,

Let me try to rephrase this and tell me if it sounds right...

"I was solving a problem and the question is to simplify the circuit . I didnt understand how the whole circuit is the same as the sum of I1 and I2. U1 (which is a voltage source ), I3, and R1 dont play a role."

Does this sound right?

exactly

 

Amazing what a missing punctuation does to the meaning. Consider:

"We are going to stop and eat, John, before we take another step."

"We are going to stop and eat John, before we take another step."

Which one has cannibalistic overtones?

 

I meant the sum if Í1 and i2 if you are unsure you could see the image

What current HAS to leave the upper terminal (A) in order to satisfy KCL?

What current then HAS to enter the lower terminal (B) in order to satisfy KCL?

The current sources will produce whatever voltages across them that are needed in order to make this happen. Changing U1 or R1 merely change the specific voltages that the current sources need to produce in order to make that happen.

Put a load resistor, R2, across (A) and (B) and calculate the current through it and also the voltage across the various current supplies and the current through (and voltage across) R1 plus the current through R1. That should shed some light onto how this all plays out. You should also see how most of these quantities can be written down by inspection.