# current through inductor

#### vvkannan

Joined Aug 9, 2008
138
I have a doubt about regarding inductors
If i connect a 1v source to an 1H inductor (without a resistor) would the current vs time(x axis) graph be a straight line with slope 'one' passing through the origin before reaching the curent reaches a constant value?

#### vvkannan

Joined Aug 9, 2008
138
Thank you for replying.I meant to ask what would exactly happen if there is nothing in the circuit except the constant voltage source and inductor.
The inductor would oppose the current initially.so zero current.and at steady state say a constant current flows.In between (though a very small time) will it be a straight line(i.e) a line with slope 1 if voltage is 1v and inductance is 1H according to the equation i=(1/L)*(integral(V dt)).

#### mik3

Joined Feb 4, 2008
4,846
It will be a straight line to a close approximation because inductors are not purely inductive, they have resistance too due to the copper wire.

#### steveb

Joined Jul 3, 2008
2,431
Strictly speaking, the response is an exponential shape, but initially is will look very close to a straight line. This assumes you are asking about doing an actual experiment, which your question seems to imply.

Obviously, theoretically, a perfect inductor and perfect voltage source would create a straight line (with slope 1) that goes to infinity and never reaches a constant value.

#### vvkannan

Joined Aug 9, 2008
138
I understand.Thank you

#### hgmjr

Joined Jan 28, 2005
9,029
Strictly speaking, the response is an exponential shape, but initially is will look very close to a straight line. This assumes you are asking about doing an actual experiment, which your question seems to imply.

Obviously, theoretically, a perfect inductor and perfect voltage source would create a straight line (with slope 1) that goes to infinity and never reaches a constant value.
It is my understanding that an ideal inductor when driven from an ideal voltage source is described by the equation:

$\frac{\Delta i}{\Delta t}\ =\ \frac{V}{L}$

Where $\frac{\Delta i}{\Delta t}$ is the change in current with respect to time having the units of $\frac{Amps}{Second}$ which equates to the slope of the curve,
and V equals the applied ideal voltage expressed in Volts and L is the inductance of the ideal inductor expressed in Henries.
The slope in this case would vary depending on the value of V and L. There are of course values of V and L that would produce a slope of 1. An example would be a 1H inductor together with a 1V source.

hgmjr

#### steveb

Joined Jul 3, 2008
2,431
It is my understanding that an ideal inductor when driven from an ideal voltage source is described by the equation:

The slope in this case would vary depending on the value of V and L. There are of course values of V and L that would produce a slope of 1. An example would be a 1H inductor together with a 1V source.

hgmjr
Yes, that's what I meant, but I should have been more clear. His question specifically mentions 1V supply with 1 H inductor. So, I was just trying to address his question.