Carry over from unrelated thread.
A thought experiment of a simple circuit--shown below.
If you build the circuit to find the answer,can you keep it to your self until such time as the thought experiment has been concluded. We then can all build the circuit,and share our finding's and understandings of the inductors behavior in this circumstance.
First up,lets talk LEDs.
We have say a standard 10mm white LED,and this LED conducts fully at 3 volts.
Now,we know when we have a 3 volt potential across the LED of the correct polarity a current must flow,and the current flow is in the direction indicated by the diode arrow of the LED.
So we first look at diagram 1 (V1).
This is pretty straight forward .
During the on time,current flows through D1,L1,and R1 as indicated by the blue arrow.
When the source is switched off L1 then becomes the source,and current flows through R1 in the direction indicated by the red arrow,and through L1 in the same direction as it was when the FG was the source.
Now we look at diagram 2 (V2)
We have the same coil,wound in the same direction,but we have tapped into the center of the windings,and added two LEDs between the windings.
When the FG is on,we once again see the current flow through D1,L1,R1,and now LED2.
LED2 see's a potential of 3 volts across it,and it starts to conduct,and current flows through L1 as in the first test.
But what happens this time when the FG switches off,and the magnetic field starts to collapse ?.
As you state,we see a reversal of voltage across the coil.
We now see in excess of the needed 3 volts across LED1,of the right polarity for the LED to conduct-->but the current flow is in the wrong direction !apparently! for that LED to work
So we have the correct potential now the FG has switched off,and the voltage across L1 has inverted,and enough voltage for LED1 to light,but the diode part of LED1 will not allow current to flow in that direction,as the current is suppose to continue to flow in the same direction once the source is disconnected-->right
So,will Led1 light up when the source(FG) is disconnected,and the field starts to collapse?
Or will the current continue to flow in the same direction through LED2 when the field collapses ?.
Brad
Never let your schooling get in the way of your education.
Author
Topic: Coil Antics (Read 9964 times)
