# Analogue Circuits .. #2

#### ironasona

Joined Nov 12, 2020
53
Hi ,so am currently doing homework , and was wondering if anyone could tell me if i have done my calculations correctly ,because am not 100% sure . Thank you

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#### RBR1317

Joined Nov 13, 2010
709
When calculating the current through the coil at 50hz what happened to the wire resistance?

#### MrAl

Joined Jun 17, 2014
10,590
Hi ,so am currently doing homework , and was wondering if anyone could tell me if i have done my calculations correctly ,because am not 100% sure . Thank you
Again i get results very very close to yours with only a very slight difference. I get:
3.94 amps and L=0.185 Henries.
I always wait until the end to round though.

#### LesJones

Joined Jan 8, 2017
4,013
In the second test you are actually measuring the total impedance of the coil. You then need to work out the part that is just the inductive reactance. Then from this calculate the inductance.

Les.

#### MrAl

Joined Jun 17, 2014
10,590
In the second test you are actually measuring the total impedance of the coil. You then need to work out the part that is just the inductive reactance. Then from this calculate the inductance.

Les.
So how far off are you saying he is, because i got the same answer or very very close anyway.

#### LesJones

Joined Jan 8, 2017
4,013
I have not bothered to do all the calculations. BUT the total impedance with 2 amps at 60 hz is 70 ohms. (Not 70.17)
He then needs to remove the effect the 5 ohms resistance makes to get the component that is just inductive reactance.
He has treated the 70 ohms as just the inductive reactance then added in the the effect of the 5 ohm resistance.
Also when doing the 230 volt calculation he has not added in the effect of the 5 ohm resistance to the inductive reactance as pointed out by RBR1317.

Les.

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