How Does Inductance Affect a DC Circuit?

In summary, the conversation discusses a circuit consisting of a 0.2 H inductor and a 330 Ω resistor connected in series to a 12V DC supply. The time constant of the circuit is calculated to be 0.0006 seconds. The group is unsure of how to calculate the voltage drop across the inductor and resistor after two and three time constants. They also discuss finding the resistance of a 0.2 H coil to replace the inductor if the time constant of the circuit changes to 0.55 ms. After some calculations, they determine that the resistance of the coil would be 33 Ω.
  • #1
debreets
3
0
An inductor of negligible resistance and an inductance of 0.2 H is
connected in series with a 330 Ω resistor to a 12V d.c. supply.
Determine:
(a) the time constant of the circuit
(b) the voltage drop across the inductor after two time constants
(c) the voltage drop across the resistor after three time constants
(d) the resistance of a 0.2 H coil used to replace the inductor if the
circuit’s time constant falls to 0.55 ms.

I have answer a) using formula t = L/R L is 0.2 and R being 330, t giving 0.0006 seconds ( or 0.6 ms )
Im unsure of b) and c) but will spend time on those shortly.
Part d) looked simular to a) I thought maybe use the same formula (t=L/R) but make R the subject, that would be R=t/L.
I plugged in 0.00055 for t and 0.2 for L, giving an answer of 363.63? time was given as 0.55 ms so converted to seconds giving 0.00055.
Am I on the right track or have I gone wrong?
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
debreets said:
I know this is an old thread but I am struggling also, I have answer a) using formula t = L/R L is 0.2 and R being 330, t giving 0.0006 seconds ( or 0.6 ms )
Im unsure of b) and c) but will spend time on those shortly.
Part d) looked simular to a) I thought maybe use the same formula (t=L/R) but make R the subject, that would be R=t/L.
I plugged in 0.00055 for t and 0.2 for L, giving an answer of 363.63? time was given as 0.55 ms so converted to seconds giving 0.00055.
Am I on the right track or have I gone wrong?

They are asking for the resistance of a new inductor if it has the same inductance and it is put in series with the 330 Ohm resistor. So, you have a number that is on the way to getting the right answer.
 
  • #3
Thanks for your reply,
I'm confused as I believe iv worked out the resistance of the inductor at 363.63 ohms, so would the resistance of the coil not be the same?
 
  • #4
debreets said:
Thanks for your reply,
I'm confused as I believe iv worked out the resistance of the inductor at 363.63 ohms, so would the resistance of the coil not be the same?

No, because this new circuit is still factoring in the 330 Ohm resistor that is connected when you are calculating the total resistance.
 
  • #5
Ok, so, 363 (reistance of ciruit) - 330 (resistance of resistor in circuit) = 33 ohm (resistance of coil)
Think iv got it now,
Thanks for your help
 

FAQ: How Does Inductance Affect a DC Circuit?

What is inductance in a DC network?

Inductance in a DC network refers to the property of a circuit or component to resist changes in the flow of electrical current. It is caused by the presence of an inductor, which is a passive electronic component that stores energy in the form of a magnetic field.

How does inductance affect the behavior of a DC circuit?

Inductance can cause delays in the flow of current, which can lead to changes in voltage and affect the overall performance of a DC circuit. It can also block the flow of direct current and allow alternating current to pass through.

How is inductance measured in a DC network?

Inductance is measured in units called henries (H). It can be measured using an inductance meter or calculated using a formula that takes into account the number of turns in the inductor, the cross-sectional area, and the material of the inductor.

What factors can affect inductance in a DC network?

The amount of inductance in a DC network can be affected by various factors, including the number of turns in the inductor, the type of material used, the size and shape of the inductor, and the presence of nearby magnetic fields.

How can inductance be minimized in a DC network?

There are several ways to minimize inductance in a DC network, including using shorter and thicker wires, using materials with lower permeability for inductors, and avoiding the placement of inductors near other magnetic components. Additionally, using a capacitor in parallel with an inductor can effectively cancel out the inductance and improve the overall performance of the circuit.

Similar threads

Replies
8
Views
10K
Replies
10
Views
6K
Replies
4
Views
4K
Replies
18
Views
2K
Replies
8
Views
842
Replies
6
Views
2K
Replies
1
Views
470
Back
Top