I searched practically all of the nets and webs and still my questions are unanswered, so I decided to consult y'all. I have previously asked you guys about diode sizing to prevent back emf on a relay and you were very helpful. I am once again calling upon your help. I have some relays in my design of a pushbutton starter and they need back emf suppression. Right now, they each have a simple diode running inverse and parallel to the coil. I did some more reading, and apparently, that isn't the best solution. The single diode causes the opening time of the contact to increase and causes prolonged arcing which reduces contact life. I read (here and here) that a zener run in series to a normal diode provides the best solution. So that's just fine and dandy. But then I came across transient voltage suppression diodes, aka transorbs. They are designed for this, right? So can I just replace my single diode setup with a transorb and be done with it, or is it still ideal, when using transorbs, to also have a normal diode in series with it? On the topic of sizing a transorb, I ran across this article. It seems informative, but I can only understand about half of it. Any help on how to size it would be, well, helpful. I also have one relay that will be getting current going both ways through it's coil. If I can just use a transorb, than I would get a bidirectional one and that's that. If it's best to use the zener and normal setup, can/should I just double up and mirror the zener/normal circuit? As I understand it, the other option available to me is to use a resistor instead of any diodes. That sounds good to me, but I have no freaking clue on how to size it. A bit of topic, but while I have the experts here, I shall ask. I have some relays driving other relays. Should the coils of the driven relays be suppressed as well? My only concern is that the spike from the driven relay will cause arcing across the driving relay's contacts. Is that a legitimate concern? To make it easier, here is what I'm asking: 1. Can I use a single transorb to replace my diodes, or should I use a zener somewhere in there as well? 1a. (If so) How do I size a transorb? 1b. (If not) Can I make a zener/normal setup bidirectional simply by mirroring it? 2. (If applicable) How do I figure out what resistance is needed if I am to use a resistor instead of any sort of diode? 3. Should I also suppress the coils of relays that are driven by other relays? Thanks for any help that you may be able to provide.