For the sake of this exercise, set the equipment power setting at a high enough level so that it is easy for you to generate the arc. Then slowly decrease the distance between the tip of the electrode and the surface. While you are slowly decreasing the distance, at a certain point the spark will take place (see the Paschen Law
). In order to extinguish the arc simply increase the distance again. You will notice that the higher the power setting of the device the wider the minimum distance required to generate the arc, conversely the lower the power setting the closer the tip of the electrode needs to be in order to start generating the spark.
The following experiment is meant for you to understand why (with this particular portable device) it is recommended to place your other hand on the client's body while you are applying the AC voltaic arc. With this particular battery-powered device, in this experiment, set the output power at maximum level. Start trying to generate the arc but keep the other hand away from the meat. Now as the arc is generated touch the meat with the other hand. Notice how the arc increases in power as you touch the meat with the other hand, conversely the power is much lower when you do not touch the meat with the other hand. This is because when you touch the meat with the other hand the high frequency current has an extra low resistance path to earth which decreases the overall resistance it encounters therefore increasing the power of the arc and hence the carbonisation effects.