introduction to electronics part 5 coils in DC circuits.

As you can see when I close the switch current doesn't build immediately. 

I added a resistor to limit the current. It looks a lot like the capacitor curve, only in reverse. With the capacitor current starts at max and decays. with the coil current builds with time.

When I raise the resistor value it reduces the charge time.
TC = L/R remember raising the resistor with the capacitor increased the TC.
TC = R*C

The coil opposes a change in current. How? Why?
That will be the subject of the next post.