How is the slider connected to the switch?

AI Thread Summary
The discussion focuses on understanding the role of resistors in a potentiometer circuit and how closing a switch affects current flow. It clarifies that closing the switch provides an additional path for electrons, which can increase current unless the resistance is infinite. Participants emphasize the importance of calculating total resistance in different circuit configurations to understand current behavior. The conversation also touches on the relevance of the original post title, which seems disconnected from the main question. Ultimately, the user expresses gratitude for the clarity gained through the discussion and calculations.
Physical_Fire
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Homework Statement
Check the attachment
Relevant Equations
V=IR
Hi,
I do not understand how the resistor affects the current in this potentiometer circuit. I asked my classmate and they said the switch is connected to the battery but I do not understand how. Why does the current increase?

1742369990733.png


1742370003934.png
 
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Physical_Fire said:
Homework Statement: Check the attachment
Relevant Equations: V=IR

Hi,
I do not understand how the resistor affects the current in this potentiometer circuit. I asked my classmate and they said the switch is connected to the battery but I do not understand how. Why does the current increase?
Redraw the diagram, switch closed, just showing the resistances and the battery. What is the resistance of the circuit?
 
what does this show?

1742374330509.png
 
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Physical_Fire said:
what does this show?
A voltmeter is a very high resistance, ideally infinite. So you can delete that connection.
Write an expression for the total resistance of the circuit.
Do the same for the switch open. Which resistance is higher?
 
Physical_Fire said:
what does this show?
Here are some exercises for you:
1742378313279.png

1) What is the total resistance of the first (uppper) circuit?

2) What is the total resistance of the second (lower) circuit?

3) If you have two resistors, R1 and R2 in parallel, which
of the following is true about their total resistance, Rtot:
a) Rtot is always more than R1
b) Rtot is always more than R2
c) Rtot is always less than R1
d) Rtot is always less than R2
e) none of the above.

By the way, why is the title of your post "How is the slider connected to the switch?"? This appears to have nothing to do with the question!

EDIT: I had written and posted this before I saw @haruspex's reply. I hope it helps. Not trying to butt-in.

EDIT2: My LaTeX has vanished!
 
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Physical_Fire said:
I do not understand how the resistor affects the current in this potentiometer circuit.
In the following diagram, each color represents a different value of current (I):

51b9f71bce395fb22a000000.png


Physical_Fire said:
Why does the current increase?
Closing the switch adds another possible path for electrons (being pushed by the battery’s potential difference) to flow around the circuit (unless the value of that additional resistence is infinite).
 
Steve4Physics said:
Here are some exercises for you:
View attachment 358695
1) What is the total resistance of the first (uppper) circuit?

2) What is the total resistance of the second (lower) circuit?

3) If you have two resistors, R1 and R2 in parallel, which
of the following is true about their total resistance, Rtot:
a) Rtot is always more than R1
b) Rtot is always more than R2
c) Rtot is always less than R1
d) Rtot is always less than R2
e) none of the above.

By the way, why is the title of your post "How is the slider connected to the switch?"? This appears to have nothing to do with the question!

EDIT: I had written and posted this before I saw @haruspex's reply. I hope it helps. Not trying to butt-in.

EDIT2: My LaTeX has vanished!
Thank you for this. I finally understood everything. While assuming R=2, 1/Rt = 1/9 + 1/2, so Rt = 117/91, and then using V=IR it's clear that current has increased. The voltmeter reading should decrease then as the P.D across the 9 Ohms wire (to the right connected to - terminal) will increase, the overall P.D should sum up to 6.2 V. Thanks @haruspex @Lnewqban as well.
 
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