Is my solenoid's resistance too low?

In summary, the resistance of the solenoid being discussed is calculated to be 0.175ohms using the formula R = (rho * L) / A. This may seem low, but it is sufficient as long as the chosen wire size can handle the expected current of 10A. However, inductance may also play a factor and a power supply with low voltage and high current may be needed.
  • #1
thomsonm
13
0
I've just calculated the resistance of a solenoid I'm making, but it seems far too low.

240 turns of 1.6mm wire, 30 turns per row, 8 rows deep.

total length of wire (L) = 21.96m
area of wire (A) = pi * (0.0008)^2 m^2
resistivity of copper (rho) = 1.6*10^-8 ohms m^-1

R = (rho * L) / A
R = 0.175

Is the resistance of my solenoid really only 0.175ohms?
 
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  • #2
There will initially be some inductive reactance as well...
 
  • #3
How 'low' the resistance of something is really doesn't mean anything. Someone once asked me how low of a resistance you could get 'before it shorts out'. A meaningless question. If the wire size you have chosen will handle the current you end up putting through there without burning up then you are fine. So what kind of current do you expect to put through the solenoid?
 
  • #4
I'm need 10A to get the right magnetic field.
 
  • #5
Ideally, an inductor would have zero resistance.
To supply a solenoid satisfactorily you tend to need an unusual sort of power supply - low voltage and loads of current available.
 

1. What is the formula for calculating the resistance of a solenoid?

The formula for calculating the resistance of a solenoid is R = (μ0 * N^2 * A) / l, where μ0 is the permeability of free space, N is the number of turns in the solenoid, A is the cross-sectional area of the solenoid, and l is the length of the solenoid.

2. How does the number of turns in a solenoid affect its resistance?

The number of turns in a solenoid is directly proportional to its resistance. This means that as the number of turns increases, the resistance also increases. This is because with more turns, there is a greater length of wire for the electrons to travel through, resulting in a higher resistance.

3. Does the diameter of a solenoid affect its resistance?

Yes, the diameter of a solenoid does affect its resistance. A larger diameter means a larger cross-sectional area, which leads to a lower resistance. This is because the electrons have a wider path to travel through, reducing the overall resistance of the solenoid.

4. How does the length of a solenoid impact its resistance?

The length of a solenoid is inversely proportional to its resistance. This means that as the length increases, the resistance decreases. This is because a longer solenoid has a longer path for the electrons to travel through, resulting in a lower resistance compared to a shorter solenoid.

5. What is the unit of measurement for resistance of a solenoid?

The unit of measurement for resistance of a solenoid is Ohms (Ω), named after the German physicist Georg Ohm who first discovered the relationship between voltage, current, and resistance.

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