I have a PCB coil ( 32 layer, each layer has 8 turns) and the outermost dimensions of the coil are 600 mm x 4.5 mm, resistance is around 11k Ohm.
I would like to measure the total inductance of this coil, I tried with an LCR meter in parallel configuration but it is showing a negative value of L at any frequency until 100k Hz.
Can someone please help me understanding what I'm doing wrong?
I have a PCB coil ( 32 layer, each layer has 8 turns) and the outermost dimensions of the coil are 600 mm x 4.5 mm, resistance is around 11k Ohm.
I would like to measure the total inductance of this coil, I tried with an LCR meter in parallel configuration but it is showing a negative value of L at any frequency until 100k Hz.
Can someone please help me understanding what I'm doing wrong?
Assuming the resistance is measured at DC 11k seems very high resistance for an inductor. For 256 turns that's 43 ohms per turn, something is wrong here, are the connections between layers OK?
If the tracks are thick you may be measuring capacitance between layers.
Assuming the resistance is measured at DC 11k seems very high resistance for an inductor. For 256 turns that's 43 ohms per turn, something is wrong here, are the connections between layers OK?
If the tracks are thick you may be measuring capacitance between layers.
Assuming the resistance is measured at DC 11k seems very high resistance for an inductor. For 256 turns that's 43 ohms per turn, something is wrong here, are the connections between layers OK?
If the tracks are thick you may be measuring capacitance between layers.
Right, resistance value around 11k is expectable for 50 µ traces (about 38 µ effective width with usual etch factor). I wouldn't have thought that you are using so high density.
Did you estimate interwinding capacitance and self resonance frequency?
Is your VNA lower frequency limit low enough to show self resonance frequency?
If winding capacitance has a significant effect on total coil impedance in frequency range of interest, it's not possible to determine the coil inductance by a single frequency measurement. You can either choose a significant lower frequency as suggested in post #3, or derive L and C components from a multi frequency measurement.
A VNA measurement is a possible way, however the large ratio of DC series resistance to 50 ohm doesn't promise much accuracy.
By the way, what's the intended operation frequency of your coil?
Unfortunately, your coil must have a lot of work and expense but can serve no purpose as it is too lossy (resistance) with tracks so narrow and undefined L/R ratio and L/C ratio. Perhaps if you share your intent, we can help.
Unfortunately, your coil must have a lot of work and expense but can serve no purpose as it is too lossy (resistance) with tracks so narrow and undefined L/R ratio and L/C ratio.
Strictly speaking, you can't know without an operation frequency specification. But the 100 kHz LCR measurement frequency mentionend in post #1 gives rise to doubts.