Electronics > Beginners
Low frequency coil arrangement
LaserTazerPhaser:
Is there a particular arrangement/winding method for aircore coils yielding very low LC frequency =<2khz with the L being =>1000uH without using any external capacitors to lower the frequency?
magic:
In general, increasing diameter and decreasing length both have a double effect of increasing inductance and parasitic capacitance.
I have not a faintest clue how far you can take it in practice.
edit
You know the drill: 1/f=2π·sqrt(LC)
To get below 2kHz, you need L·C of at least a few nano if my math is right. That may be hard since capacitance of any reasonable coil is probably in the pico- range.
radiolistener:
Use coil diameter equals to the coil length, it gives best coil parameters
soldar:
I am not sure I understand what you are asking but a rough calculation tells me a coil with 4 cm external diameter, 6 cm length and 800 turns has about 13000 uH and coupled with a 1 uF capacitor it would resonate at 1.4 KHz.
At such low frequency skin effect should not be a consideration and I cannot think any other reason you cannot just wind it. Except that I have not calculated if you can physically construct such many turns in that space.
Kleinstein:
Normally one want a high self resonance frequency, thus minimize the parasitic capacitance.
To get self resonance at only 2 kHz would need a lot of parasitic capacitance. More like using material normally used to build a capacitor, like thin foils to make a 1 µF cap with some mH inductance. It may work if you think large, that is 10s of meters in diameter and using lots of wires in the "wrong" ordering. That would than be more like inductance in the H range and some nF of parasitic capacitance.
I would go for an external capacitor.
Navigation
[0] Message Index
[#] Next page
Go to full version