# simulating a lightning generator

I didn't have much input with the original post, so I'm taking a different approach now. How do I model a transient/lightning source whose output looks like the shown waveform when connected to the load (a filter that contains TVS diodes/transorbs that clamp the voltage)

Additional info: As seen in the output waveform of an actual transient generator, the output voltage hits plateau, stays constant while the current rises and falls in a parabolic path. enter image description here![enter image description here][1]![enter image description here][2]

• Is this to a particular specification? I have to deal with 6kV pulses with 1.2/20 us voltage and the out put impedence of 2 ohm's google.co.uk/… – Spoon Jun 11 '14 at 19:50
• Oops its a 1.2/50 us wave form.. but that is unloaded and represents lightning in an industrial enviroment. – Spoon Jun 12 '14 at 1:08

## 1 Answer

You have the below picture of an idealized transient you want to recreate: -

Comparing the current waveform with the voltage waveform tells you that this cannot be the current thru a capacitor (as shown by C2 in your schematic). This is because

$I_{C_2}$ always must = $C\cdot \dfrac{dv}{dt}$

Clearly, in your idealized voltage waveform, there are "points" where the voltage change with time would result in an obvious "disturbance" in the current and that is just not seen in the picture. Also, the current returns to zero (apparently) whilst the voltage is still decaying. This cannot happen with a simple capacitor load like C2.

I believe you need to rethink what you are trying to achieve and what might help is trying to find the transient specification for the generator you are hoping to emulate. Most transient generators will have some equivalent circuit and I've definitely seen a couple on the web so maybe keep searching.