Driving a coil Voltage drive? Current drive?

In summary, driving a coil with a voltage or current source can affect the resonance frequency and Q factor of the coil.
  • #1
kent
13
0
Driving a coil...Voltage drive..? Current drive..?

Hi Guys

As the title...I am now having a 10 turns coil, does it really matter that I drive it with sinusoidal voltage signal or a sinusoidal current signal? Will it affect the response of the coil? (like resonance frequency, Q factor...etc)

I am still doing the mutual inductance experiment..(thanks for u guys' help previously! especially Berkeman and Waht)...I am now having a identical coil as the transmitter to be a magnetic induction detector (properly shielded..) what I observed is that the Q factor of my detecing coil is extremely high~! the magnitude of the detected signal at resonance is like 30 times more than the other frequencies...is that a normal observation?

And also, I am now thinking using a PCB coil instead of hand made coil (to make sure all the coils are identical...)Does anyone has this kind of experience? (like the shielding of the PCB...etc)

Thanks you so much for you guys' time!
Kent
 
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  • #2
If you drive a coil with a voltage source, it needs to be in series with a load resistor (if there is one). And likewise, with a current source the coil or anything else for that matter should be in parallel with the load resistor (if there is one).

Resonance is a weird thing, under right conditions when driving an LC circuit with a voltage source in series, you can have large voltages developing, even a 1000 times higher then what you put it, if the Q is really high, but the current would be 1000 times less, and likewise, if you drive an LC circuit with a current source in parallel, large currents will develop, so much so that can even melt your coils when Q is high enough, but voltage will drop of course. That's why sometimes it's good to broaden the Q by inserting a load resistor to absorb some current.

You said your coil has ten turns, so it might have a like 500uH or something, it might be difficult to duplicate the coil on a PCB, and even if you do it will have a different Q, and coupling constants.

And for PCB shielding, anything conductive and grounded placed over the PCB will shield the circuit from the outside world. Nothing significant will get in or out.

Hope that helps.
 
  • #3
Thanks you!...The size of my coil is quite small...so the inductance of my coil is around 10uH...which is OK...I think...
 
  • #4
I meant 500 nH not uH sorry. That's what you would typically get with a small 10 turn coil. Coils etches on pcb's are in nH range.
 

What is the difference between driving a coil with voltage and driving it with current?

The main difference between driving a coil with voltage and driving it with current is the way in which the energy is delivered to the coil. When driving a coil with voltage, the energy is supplied in the form of an electrical potential difference, or voltage, across the coil. This creates an electric field within the coil which induces a magnetic field. On the other hand, when driving a coil with current, the energy is supplied in the form of an electrical current flowing through the coil. This creates a magnetic field within the coil.

Which method is more efficient for driving a coil?

The most efficient method for driving a coil depends on the specific application and the characteristics of the coil. In general, current drive is more efficient for larger coils, while voltage drive is more efficient for smaller coils. This is because larger coils have a higher resistance and therefore require more voltage to drive the same amount of current. Additionally, current drive is more efficient for applications where a high magnetic field is required, while voltage drive is more efficient for applications where a high voltage is required.

What are the advantages of driving a coil with voltage?

Driving a coil with voltage has several advantages. One of the main advantages is that it allows for precise control over the strength and direction of the magnetic field. This is because the voltage can be easily adjusted to change the strength of the electric field, which in turn affects the strength of the induced magnetic field. Additionally, voltage drive is less affected by external factors such as temperature, which can impact the resistance and therefore the efficiency of current drive.

What are the advantages of driving a coil with current?

One of the main advantages of driving a coil with current is that it is more efficient for larger coils, as mentioned earlier. Additionally, current drive is generally more stable and less prone to fluctuations compared to voltage drive. This is because the current flow remains constant, while the voltage can fluctuate. Current drive is also less affected by factors such as coil resistance, making it more reliable for certain applications.

Which method is commonly used for driving coils in scientific experiments?

The method used for driving coils in scientific experiments depends on the specific experiment and the requirements of the coil. However, voltage drive is commonly used for precision experiments where precise control over the magnetic field is needed. On the other hand, current drive is often used for larger coils and experiments where stability and efficiency are important.

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