How many meshes are in this circuit?

Question

Aren't there three meshes here? The solution also says so. I denoted the three loops that I think are meshes, but the instructor said in class that there are 5 meshes. I just cannot find the other two.

Edit:

Are these the five meshes?

Answer 1

This is likely drawn improperly. Or it's intended to trick you. For example, the 80k resistor reduces to a short circuit. As does the 2A source. But you could argue the short that it forms with itself is a mesh (ground potential everywhere). In other words, there's a lot of reductions that can take place from electrical axioms without even doing any math, which is usually the intent of nodal and mesh analysis.

So assuming no one is trying to trick you, and the degenerate cases are allowed, there are 5 meshes, two of which you correctly identified. All 5 are as follows:

• Ground, 100V source, 10k resistor, Ground
• Ground, 4V source, 20k resistor, Ground
• Ground, 40k resistor, 120V source, Ground
• Ground, 2A source, Ground
• Ground, 80k resistor, Ground.

If you simplify this down, you are left with a less than stellar 3 independent loops that have a common ground: all amount to a voltage source across their respective resistor. The right side (current source and 80k resistor) is some sort of meme without additional context.

Separate note: The question in the problem states "Determine the number of nodes in the problem."

The answer in the problem states "Ans: 3 mesh"

Kind of weird.