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This research aims to develop a pulse high voltage generator for stimulating Pleurotus Sajor-Caju mushroom by using impulse generator circuit. The circuit was developed with 10 nF of capacitor, 500 kOhm of resistor and 3.56 mm distance of spark gap, resulting in 11,800 V for sparking. The experiments consisted of the pulse high voltage generator with 5, 10 and 15 stages which would obtain 48,000, 93,000 and 140,000 V, respectively. Specifically, it is a switching impulse. The front time and tail time (T1/T2) of wave form are 0 and 3,400 ms. The stimulation was done on Pleurotus Sajur-Caju mushroom, made from a bag of sawdust-based for growing Pleurotus Sajur-Caju mushroom. From the total of 24 bags, they were divided into four groups during the stimulation: Group 1 for 50,000 V, Group 2 for 100,000 V, Group 3 for 150,000 V and Group 4 for the control group which was not at all stimulated by pulse high voltage. During the experiment, each mushroom was stimulated by pulse high voltage 20 times and allowed 60 days for growing. The total yield of mushroom revealed that the minimum productivity was found to be the control group which was only 754 grams. As for the experimental groups, they were 806 grams for the 50,000 V group, 849 grams for the 100,000 V group and the maximum was 853 grams for the 150,000 V group. It can be concluded that the maximum productivity of Pleurotus Sajor-Caj mushroom could be stimulated with 150,000 V pulse high voltage, which increased its productivity by 13% when comparing to the control group.
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