Frequency and capacitors in magnetic heating

08 Jul Frequency and capacitors in magnetic heating

Within the D5 Series instruments for magnetic heating experiments, the Driver is the main device where capacitors, coils and accessories are connected. The relation between the frequency and the capacitors is vital to understand the performance of this magnetic heating instrument. The Driver can generate any working frequency between 100 kHz and 800 kHz and it’s controlled by software Maniac. The production of the alternating magnetic field (AMF) is done through resonating circuits that physically combine CoilSets and capacitors. That means that the actual available working frequency of the magnetic heating instrument depends on the combination of CoilSets and capacitors available, meaning on the Driver as it will be described below.

Planar CoilSet PC70 connected to F1 Driver and two external plugged-in capacitors.
Image 1. Driver F1 with Planar CoilSet PC70 and two external plugged-in capacitors.

So, the working frequency at any given time depends on the inductance of the CoilSet connected and the capacitance of the capacitor or the combination of capacitors connected. In this way, the combination of one CoilSet and one capacitor provides only one frequency, which is called the resonance frequency. 

G Drivers and F Drivers

D5 Series offers different Drivers to choose from depending on each user’s requirements of magnetic field and number of frequencies available. According to the frequency modes provided, there are two different groups: G Drivers and F Drivers. Then, there are different models according to the power and the maximum magnetic field achievable, where F3 and G3 Drivers are the most powerful.

G Drivers (G2, G3) provide an internal bank of four combinable capacitors, resulting in fifteen available combinations of capacitors without the need of any hand work. So, when a CoilSet is connected, the system automatically provides fifteen different resonance frequencies interchangeable automatically by software Maniac. Additional frequencies can also be provided by manually connecting an external plug-in capacitor. Thus, sixteen additional frequencies per CoilSet will be available with each extra capacitor, resulting in a total of thirty one frequencies.

Front and rear view of an external capacitor for D5 Drivers
Image 2. External plug-in capacitor (front and rear view)

F Drivers (F1, F2 and F3), on the other hand, do not have any internal capacitor, so at least one external plug-in capacitor is required to provide one frequency. In addition, they are able to have 2 different external capacitors connected at the same time which would provide 3 different frequencies, given all the possible combinations between them. 

Therefore, there is no limit to the number of frequencies for all D5 Drivers, and all of them, from F1 to G3, can be set to any frequency from 100 KHz to 800 KHz. G Drivers make the frequency sweep experiments much more practical and productive whereas F Drivers provide a more economical option without loosing power if having many frequencies is not the priority.

Detail of the two external capacitors connected to F1 Driver.
Image 3. Two external plug-in capacitors connected to F1 Driver

Furthermore, the use of external plug-in capacitors offer the possibility of other applications making this instrument so much more versatile.

Cable Extension for CoilSet

This new accessory has been designed to provide the possibility of conducting different experiments on other instruments while at the same time an AMF is applied by D5 Series instrument. The CoilSet is the area of AMF application where the sample is located so this offers the opportunity to run other additional tests simultaneously and measure different parameters using other instrumentation.

The Cable Extension for CoilSet features two joint flexible cables long enough to take the CoilSet to the desired instrument. It has two terminals at one end to connect to the Driver and a small station at the other end to plug in the external capacitor and the CoilSet.

This accessory is just an example of the endless possibilities the D5 Series along with the external capacitors can bring to magnetic heating experiments.

Cable Extension for CoilSet connected to Driver F1 and S56 CoilSet
Image 4. Cable Extension for CoilSet connected to F1 Driver.
Detail of the external capacitor of the Cable Extension for CoilSet.
Image 5. Detail of the external capacitor of the Cable Extension for CoilSet.


D5 Series Solenoid CoilSet

Sample positioning in Solenoid Coils

Knowing in detail the geometry and other manufacturing parameters of the coil, the magnetic field distribution and therefore the effective volume are essential for a good positioning of the sample to maximize nanoparticle heating in Solenoid Coils.