What is rise time?

[Philmore Rial]

This might be a moot point. Essentially all the variables are decided at the point of materials selection. Engineers choose the materials based on their LCR (inductive/capacitave reactance) physical properties. Once the materials are selected, the rise time cannot be altered, except external influences like supercooling, or better sheilding in the packaging, or optimizing component and conductor spacing, as well as conductor connectors. Connectors are always suspect. Careful circuit analysis often finds connectors make an optimum circuit a lot less than optimal.

Once designed and components assembled the rise time on a pad device will remain the same for its service life. I have switched to gold plated 4mm banana plugs and sockets on pad devices, because when measured with a TDR (time domain reflectometer) I could see the impedence of the non-gold plated sockets and plugs were not great. Then careful circuit analysis can uncover problems like cold solder joints. We tend to look for much more serious problems, but often it is as simple as a cold solder joint.


On a plasma device, the particular tube rise and fall times are determined when manufactured. Later once designed and constructed there is little that can be done to change it. LCR can be altered by spacing conductors to minimize reactances, when constructing the device. This is only the delivery to the plasma tube. So rise time/fall time is what it is, and the result of decisions made before we get our hands on it. It is an interesting discussion, but many of the material recommendations are historical/empirical and only change with the development of new technologies. Phil