# Concept of inductor

Discussion in 'General Electronics Chat' started by elecidiot, Nov 27, 2010.

1. ### elecidiot Thread Starter New Member

Jun 29, 2010
23
0
I came across this problem which is attached here as a jpg file. In the problem the switch is opened at t=0. The initial conditions before opening of switch ie at t=0- is iL1=E/R and iL2=E/(2R). This I can understand. But for finding iL1(0+) and iL2(0+) the equation
(L1+L2)i(0+)=L1(iL1(0-))+L2(iL2(0-)) is used. How this equation is got? Does this means that the currents in both L1 and L2 are changed instantaneously? Please help. See the attachment for the circuit.

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2. ### thatoneguy Expert

Feb 19, 2009
6,349
732
Is this a homework assignment?

Inductor currents do not start instantly, they resist a change in the flow of current, whether it is none, or 1 amp.

3. ### elecidiot Thread Starter New Member

Jun 29, 2010
23
0
this is not a homework assignment. this was worked out in class. i just wanted to know how this equation (L1+L2)i(0+)=L1(iL1(0-))+L2(iL2(0-)) came. Please explain that.