Current Divider Formula if R for element = 0

In summary, when analyzing a current divider circuit, it is important to recognize that zero resistance is an idealization that does not exist in the real world. If R1 were to have zero resistance, it would essentially create a short circuit and cause potential damage to the circuit. The proper formula to use for current divider calculation is I_i = Is (R_T / R_i), where R_T is the total resistance and R_i is the resistance of a specific resistor.
  • #1
cavalieregi
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Hi I was wondering say for example you had this simple current divider circuit.
Wk6BPjV.png

I was wondering if R1 for example had zero resistance it would have all current dropped over it. However pertaining to the current divider formula.

##I_i = Is (R_T / R_i)##

Thus if R1 = zero the equation is not defined but that also means R2 = RT and the equation would claim all current would be dropped over R2?
 
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  • #2
If R1 were zero then it would be a wire not a resistor, so in effect the two terminals of the voltage source would be connected directly to one another forming a short circuit. Try building this circuit and either a fuse will blow or something will break, catch on fire, or explode.

To properly analyze these situations, you have to recognize that zero resistance is an idealization that doesn't exist in the real world. Instead you must use the very small but non-zero resistance that any real wire has. When you do, you will see that the total current is very large while the current across R2 is near zero.
 
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  • #3
Where did you get that formula from? It does not seem to apply here. You should have the sum of the two resistances in the denominator.
 
  • #4
nasu said:
Where did you get that formula from? It does not seem to apply here. You should have the sum of the two resistances in the denominator.
Yes I just realized sorry. Now It makes sense.
 
  • #5


I would like to clarify that the current divider formula is used to calculate the current flowing through a specific resistor in a circuit. It takes into account the total resistance of the circuit and the individual resistance of the resistor in question. In the scenario you have described, if R1 has a resistance of zero, it would essentially act as a short circuit, meaning that all the current would flow through R1 and none through R2. This is because the current will always follow the path of least resistance. Therefore, the current divider formula would not be applicable in this situation. It is important to note that in real-world circuits, it is not possible to have a resistor with zero resistance.
 

FAQ: Current Divider Formula if R for element = 0

What is the Current Divider Formula?

The Current Divider Formula is a mathematical equation used to calculate the current flowing through a specific resistor in a parallel circuit. It is used when the resistance of one element in the circuit is equal to zero.

How is the Current Divider Formula derived?

The Current Divider Formula is derived from Ohm's Law, which states that the current flowing through a resistor is equal to the voltage applied across it divided by its resistance. In a parallel circuit, the total current is divided among the various branches based on their individual resistances.

When is the Current Divider Formula used?

The Current Divider Formula is used when there is a need to calculate the current flowing through a specific resistor in a parallel circuit where the resistance of one element is equal to zero. This is often the case when a wire or conductor is connected in parallel with a resistor.

How is the Current Divider Formula applied?

To apply the Current Divider Formula, the total current in the circuit must be known, as well as the resistance of the element in question. The formula is then used to calculate the current through that specific element. This can be useful in troubleshooting circuit problems or designing new circuits.

What are the limitations of the Current Divider Formula?

The Current Divider Formula assumes that the resistors in the parallel circuit are connected in an ideal manner, with no stray capacitance or inductance affecting the current flow. It also assumes that the voltage source is constant. Additionally, the formula may not be accurate if the resistance of the element in question is not significantly smaller than the other resistors in the circuit.

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