on one driver i built to run a car ignition coil i ran into a problem where i added inductance with some capacitance at the input caused a lager spike, my guess is that it caused ringing at the input to the driver and i could only see it on a fast scope so i lowered the values of the parts on the input side, i also added a lasorb to the input of a programmable timer, i use it as a trigger transformer for a flash lamp, i did that after i blew a timer out and so far this has worked to protect the timer. you can find oscilloscopes used on ebay and some other sites as well, what i use is a Philips/Fluke combi scope as they called them i have a PM3394 that i got for less then 150 bucks, the reason i like the combiscope is it has both analog and digital functions in one unit, new they where quite expensive but since people like scopes with an LCD display the value has gone down a lot on these units, mine is a 4 channel 200mhz but they did make them in 2 channel and lower frequency, the 3394 was there highest one i believe
http://www.ebay.com/itm/Fluke-PM3394...0AAOSwl9BWJ-HN
That's the model i have but using the search name of combiscope gets hits on most of the product line, i used one at work in the past and fell in love with it, i have two other digital ones,one is a spare and i can fix the second one i am going to try and sell it, the company that i got it from did not package it right and got it in kit form if you will, the common fault i find with these is a capacitor on the high voltage line shorts and will load down the supply to the point it may not turn on and if it does turn on you will not have any display, it's "usually" an easy fix
Remember Remember The 8th of November, When No One Stood, but Kneel, In Surrender
In a popular government when the laws have ceased to be executed, as this can come only from the corruption of the republic, the state is already lost. Montesquieu