Hello,

I have attached two different configurations that I found in two boards which perform the same task. The one with the capacitor, when the MOSFET is turned on,the voltage across the load increase smoothly, but the one with the 3 varistors in series, the voltage first increase abruptly and then stabilizes. Does that problem have to do with the varistors, or is there another problem somewhere in the board?

 

The characteristic of the cap is that its charge changes with any voltage difference.
The characteristic of the varistors is that they allow zero current until their breakdown voltage is exceeded.
You must choose whether you want fast turn on because you have not given enough information for me to decide which circuit you call a problem.