Coils Real resistance ?

[hooby life]

I making a round 27 cm coil with 18awg wire lenth about 12m , 140uh / risistance with lcrt7 are 0.73ohm . Résistance with multumetre 0.3ohm . Coil 10 cm with same wire and lenth résistance 0.3ohm with multumetre. Lcr read about 24 ohm and about 240uh
wich tru coil resistance ?

[lucifer]

12m of 18 AWG wire have 0.25 ohm resistance at 20 degrees Celsius ambient temperature. With 12 m of wire and 27 cm coil diameter you can make about 14 turns and that makes approximately 140-150 uH. Your numbers look correct and the resistance you get from your multimeter is close enough.

[hooby life]

12m of 18 AWG wire have 0.25 ohm resistance at 20 degrees Celsius ambient temperature. With 12 m of wire and 27 cm coil diameter you can make about 14 turns and that makes approximately 140-150 uH. Your numbers look correct and the resistance you get from your multimeter is close enough.

What about risistance 24ohm and 0.7 ohm in lcr ? Some times with anauthor coils give true R .and the indictance is allways tru

[Carl-NC]

LCR meters often read AC resistance instead of DC resistance. You can see this if you increase the frequency on the LCR meter and the resistance reading also increases. Some LCR meters have a true DC resistance mode, otherwise use the lowest frequency setting. Also, a lot of meters are not especially accurate at extremely low resistances. It really requires a 4-wire Kelvin probe. Lucifer is right: when in doubt, check with calculations.

[Xtrem]

Im measuring the resistance of the coils using this little tool..

https://www.e-cig.gr/en/e-cigarettes...eter-voltmeter

[hooby life]

LCR meters often read AC resistance instead of DC resistance. You can see this if you increase the frequency on the LCR meter and the resistance reading also increases. Some LCR meters have a true DC resistance mode, otherwise use the lowest frequency setting. Also, a lot of meters are not especially accurate at extremely low resistances. It really requires a 4-wire Kelvin probe. Lucifer is right: when in doubt, check with calculations.

Thank you carl inuse chinesse tansistor tester t7 my be it has auto frequency 1 khz .