Simple circuit - Where is current going?

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SUMMARY

The discussion centers on calculating the voltage at node Va in a circuit involving resistors R1, R2, and R3. Participants clarify that the voltage at Va is defined as the potential difference between Va and ground, emphasizing that ground serves as the reference point for all voltage measurements. The conversation highlights the application of Kirchhoff's Current Law (KCL) to analyze current flow at the node, asserting that the sum of currents entering the node must equal the current exiting it. This approach resolves confusion regarding the role of R2 and the overall circuit configuration.

PREREQUISITES
  • Understanding of Ohm's Law
  • Familiarity with Kirchhoff's Current Law (KCL)
  • Knowledge of voltage dividers and circuit analysis
  • Basic concepts of electrical potential and ground reference
NEXT STEPS
  • Study Kirchhoff's Current Law (KCL) in detail
  • Learn about voltage dividers and their applications in circuit design
  • Explore the concept of electrical ground and its significance in circuits
  • Practice circuit analysis techniques using various resistor configurations
USEFUL FOR

Electrical engineering students, circuit designers, and anyone involved in analyzing or designing electrical circuits will benefit from this discussion.

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Homework Statement



Find the voltage at Va.

Homework Equations



Ohm's Law, Current Divider, etc
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The Attempt at a Solution


This is the almost identical to the cookie cutter voltage divider, except that there is a resistor on the output. I'm curious if current would even flow through R2. I guess when you are asked for the voltage at a specific node, it is implied that the common is on ground. So in this case, is the answer going to be the voltage drop between Va and ground? Which might would be R2 and R3 in parallel? or something. I'm very confused.
 
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Brilliant said:
This is the almost identical to the cookie cutter voltage divider, except that there is a resistor on the output.

No, not really a voltage divider (no two resistors are in series here). And what have you defined as the output?
Brilliant said:
I'm curious if current would even flow through R2.

Why wouldn't it?

Brilliant said:
I guess when you are asked for the voltage at a specific node, it is implied that the common is on ground.

I'm not sure what you mean by "the common", but ground is the reference point relative to which all potentials are measured, yes.

Brilliant said:
So in this case, is the answer going to be the voltage drop between Va and ground?

Yes, voltage VA is defined as the potential difference between the point in the circuit that is labelled VA and ground.

Brilliant said:
Which might would be R2 and R3 in parallel? or something. I'm very confused.

I can't make sense of this, grammatically or otherwise.

Just use KCL at the node where you've hand-drawn the dot. Assume that some of the current comes into this node from the left (across the branch with R1) and some comes into this node from the right (across the branch with R2). KCL says charge is conserved (can't just disappear) therefore all of the current flowing into this node (the sum of the two currents from either side) is equal to the current flowing out of it (which is across the branch with R3).
 

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