Would the 1N4148 be considered a snubber diode?

Yes. Snubber diode, back EMF diode, and flyback diode mean the same thing.
https://en.wikipedia.org/wiki/Flyback_diode
https://en.wikipedia.org/wiki/Snubber

 

Yes. Snubber diode, back EMF diode, and flyback diode mean the same thing.
https://en.wikipedia.org/wiki/Flyback_diode
https://en.wikipedia.org/wiki/Snubber

Thank you Dennis,

Would either of these be the correct way to wire in the diode?

 

Would either of these be the correct way to wire in the diode?

The one on the left.

 

Really?!?

Wow - That seems crazy!

Obviously I'm ignorant to this, but that seems to me like touching the positive lead to the negative. ha ha.

I'll order the 1N4148 and connect it as you suggested. Thank you for all of your help!

 

Wow - That seems crazy!

Obviously I'm ignorant to this, but that seems to me like touching the positive lead to the negative. ha ha.

That's how a snubber diode works. When power is removed from an inductive load, the inductance will try to maintain the current that was flowing before power was removed. That will create a voltage across the diode that is the opposite polarity. A snubber diode limits that voltage to about 0.7V.

This how to draw your diagram as a schematic.

The resistance given for the inductor allows anyone reading the schematic to calculate the inductor current.

 

You have been super helpful!

Time for me to take some classes to understand this all better.

Thanks so much Dennis.

 

You have been super helpful!

That's what we're here for.

BTW, there needs to be a switch in the schematic I posted; otherwise, no back EMF will be generated. I just transcribed your diagram into a schematic.

 

An inductor tries to keep the current flowing when you open the circuit, so it will generate a negative going spike on the positive terminal.
The diode across the coil provides a path for that current, limiting the transient to about -0.7V.
A diode in series will have no effect on that negative spike.

 

An inductor tries to keep the current flowing when you open the circuit, so it will generate a negative going spike on the positive terminal.
The diode across the coil provides a path for that current, limiting the transient to about -0.7V.
A diode in series will have no effect on that negative spike.

Thank you. I'm trying to understand this the best I can.

Did you see my crude wiring diagram drawings? Dennis said the drawing on the left would be the correct way to wire in the diode? Do you agree with that?

 

The one on the left is correct, the one on the right will block the current to the lock.

 

The popular 1n4002/7 often used for this purpose is now available in ultra fast, UF4002/7.
Max.

 

Good info, but a fast recovery diode has no advantage for this application.

I understood a BEMF diode was being considered?
It is essentially the same as the 1N4xxx versions but ultra fast.
Max.