Experiments with LC circuits part 7

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Now I made some coils on PVC tubes with different diameters.
Each time the same piece of litzwire (660x0.04mm) is used, with a lenght of 17.5 meters.
17 meters are wounded on the coil, and there are 2 leads of 0.25 meter.

Coil L14

Windings in one layer without spacing.
Total wirelength: 17.5 meters
Number of windings: 48
Coil length: 73 mm
Coilformer: PVC tube 110 mm diameter
Induction: 234 uH

 

Coil L15

Windings in one layer with spacing.
Total wirelength:17.5 meters
Number of windings: 48
Coil length: 115 mm
Coilformer: PVC tube 110 mm diameter
Induction: 180 uH

 

Coil L16

Windings wounded in 3 layers
Total wirelength: 17.5 meters
Number of windings: about 47
Coil length: 29mm
Coilformer: PVC tube 110mm diameter
Induction: 464 uH

 

 Coil L17

Windings in one layer without spacing
Total wirelength: 17.5 meters
Number of windings: 69
Coil length: 115 mm
Coilformer: PVC tube 75mm diameter
Induction: 208uH

 

 Coil L18

Windings in one layer without spacing
Total wirelength 17.5 meters
Number of windings: 105
Coil length: 155 mm
Coilformer: PVC tube 50 mm diameter
Induction: 164 uH

 

Measurement 
number

LC combination 

F min 
kHz

F max 
kHz

Q
600 kHz 

Q
900 kHz 

Q
1200 kHz 

Q
1500 kHz 

76

L14 C2b 

526.7

2026

1224

1111

930

728

77

L15 C2b

599.7

2280

1176

1232

1090

955

78

L16 C2b 

374

738

122

*

*

*

79

L17 C2b

558.8

2217

1153

1139

1016

842

80

L18 C2b

628

2535

937

947

857

718

Conclusion:
Windings in more than one layer reduces Q
The longer the coil, the lower the induction (with equal wire length)

 

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