Silly question about voltage and current

[Dave45]

Lets add a diode for clarity,
If the bemf from the coil had a neg polarity the freewheel diode would be reversed, but it isnt this indicates the polarity of the bemf is of a pos polarity.

[Dave45]

Your IRF510 MOSFET is upside down.  Connected like that with the source to the coil and the drain to the low side of the circuit current flows continuously through the MOSFET body diode.

irrelevant to the discussion, this came from some circuit schematic I had on hand

[MarkE]

Lets add a diode for clarity,
If the bemf from the coil had a neg polarity the freewheel diode would be reversed, but it isnt this indicates the polarity of the bemf is of a pos polarity.

That configuration is actually used in a number of half-bridge power circuits to prevent conduction through the MOSFET body diode.

[Dave45]

Why is this important, because we can use the pos energy to pulse a coil, now the diode works bidirectional it passes the pos bemf from the negatively pulsed coil into another coil, pulsing this coil with pos energy its bemf will be neg and will pass through the same diode, now your coils can ring back and forth.

[MarkE]

irrelevant to the discussion, this came from some circuit schematic I had on hand

Dave, if you don't draw things correctly then it is going to throw the conversation off.