what will be the inductance of a solenoid inductor if these are its parameters:
" 5 turns, 7mm diam, 9mm length " i think it will be 100nH, am i right guys!

 

what will be the inductance of a solenoid inductor if these are its parameters:
" 5 turns, 7mm diam, 9mm length " i think it will be 100nH, am i right guys!

I came up with 120 nH using 18-24 gauge wire (the 24 gauge being such as found in Cat 5 cable).

Inductans: 120.6 nH

Coil length: 9 mm
Avg. coil diameter: 7.9 mm
Winding thickness: 900 µm

Wire length: 133 mm
Resistance: 3.5 mohm (copper wire at 20°C)

The inductance is more stable across wire sizes as the fill factor isn't 100%.

Still, you may want to use either an Oscilloscope or LCR meter to measure the actual value, then add or remove a turn to get the exact value desired.

 

the diameter is 7 mm not 7.9mm,so please check it again

 

the diameter is 7 mm not 7.9mm,so please check it again

The inside diameter is 7mm. The average diameter to the middle of the wires which make up the coil is 7.9mm.

 

what if i use AWG #18 copper wire! what will be he inductance!

 

what if i use AWG #18 copper wire! what will be he inductance!

The above was calculated for 18 gauge.