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AMG38
1 year ago

When the source is switched on, the load of the source increases, so the seed current I1 increases.

However, it would be nice that less and less electricity flows when more and more consumers are switched on;)

I2 is then reduced because the voltage at this branch is reduced by the connection. In a parallel circuit, the total resistance is smaller than the smallest individual resistance. Does not matter how large the two resistors are. I2 will always decrease when switching R3.

Gegsoft
1 year ago

When the switch is closed, current flows through R2 and R3. As a result, the voltage at R1 drops and this leads to less current flowing through R2 than with an open switch.

Therefore, answer 2 is the right one. I2 is reduced.

Blume8576
1 year ago
Reply to  Gegsoft

Are you sure the voltage at R1 drops (sinks) when the switch is closed?

The total resistance of the circuit drops in this case.

The current through R1 then rises

U = I *R

R1 is constant, the current through R1 thus also increases the voltage at R1.

Because the voltage at R2 drops, the current I2 is smaller by R2.

SchakKlusoh
1 year ago

open switch =

I1 = U/(R1 + R2)

I1 = I2

closed switch =

R2 // R3 = Rx .. .. .. .. (Rx is smaller than R2)

I1 = U / (R1 + Rx) . . . . . . . . (I1 is larger because Rx is smaller than R2)

The currents I2 and I3 (I1 =I2 +I3) can be indicated as a ratio of R2 to R3.

RareDevil
1 year ago

To A The current cannot remain the same. The total resistance changes by R3 when the switch is closed.

To B, you already have the answer from Gegsoft.

RareDevil
1 year ago
Reply to  NoResponse

How does the resistance change if one switches another parallel to a resistor? Consequently, what happens with the total resistance and with the current when U remains constant? (Ohms Law).

Think yourself. Predictions won’t hurt you. If you know the ohmic law, you can quickly get to the solution. Otherwise you know what you need to learn urgently. No one can tell you anything in the exam.

Acidbrain
1 year ago

Yes, it would have to be the last point, depending on which it would be bigger or smaller.

CatsEyes
1 year ago
Reply to  Acidbrain

Unfortunately not… 😉

kmkcl
1 year ago
Reply to  Acidbrain

That would only be right if there were negative resistances.

Sophonisbe
1 year ago

In your last question, you were told how the current is in a branch.

Turn on this knowledge. 🙂