Question about a flyback's polarity
I am confused with this flyback transformer I have.
I have a pulsed DC input on the primary coil (pulses from 0 to 15V) and that creates high voltage in the secondary coil.
When I connect that input in the opposite direction (wrong polarity) I don't get high voltage any more.
The possible explanation for this is that the primary coil has a diode in series with it.
Now, I'm confused by this because I tested if there actually Was a diode in there (by connecting a DC supply and a DC motor, in series with the coil) and the motor always works!
(also tested with a halogen light)
I put the coil in series with the motor to test if there is a diode inside. If there would be one inside, the motor should not work in one of the two cases, when I switch the pins of the primary coil.
So, as the results of the test tell me: there is no diode in series with the primary coil.
could it be possible that there is a diode in parallel with the primary coil?
If that's not possible, how come the flyback is not working when I connect the polarity incorrectly?
Could someone please help me out with this?