A 3.6V zener diode has such poor voltage regulation that the manufacturers don't show curves for them anymore.
Look at the datasheet. The 1N4729 is 3.6V with a current of 69mA through it. With this circuit's very high 32.5VDC supply, a resistor feeding it should be 419 ohms and will dissipate 2W of heat. With the 2.2k resistor feeding it, its current is only 13mA and so its voltage might be only 3.0V, then the 3V output is about 2.3V. The zener's voltage will drop more as the BD139 transistor takes current from it. Therefore the 3.0V output will not be 3.0V regulated.
Of course the 200 ohm resistor smoked if it was small, it was heating with more than 4W.
The electrodes don't do anything. The output is the same if they are shorted or open or anything in between.