drain of the first n channel mosfet 520 is connected to the source of a second n channel mosfet 523 an eighth resistor 527 is connected at a seventh node 524 to the seventh resistor 522 a ninth resistor 525 and the gate of the second n channel mosfet 523 similarly the drain of the second n channel mosfet 523 is connected to the ninth resistor 525 at an eighth node 526 also connected at the eighth node 526 is a second pull up resistor 550 and a tenth resistor 529 which is a part of the high side gate drive 501 this configuration makes up the pin scorotron grid voltage control circuit 502 the high side gate drive circuit 501 includes the positive terminal of a variable voltage source 549 which is connected to a ninth node 547 through an eleventh resistor 548 the negative terminal of the variable voltage source 549 is connected to ground 556 also connected at the ninth node 547 is the gate of a fifth p channel mosfet 546 and a twelfth resistor 543 the drain of the fifth p channel mosfet 546 is connected to ground 556 similarly the source of the fifth p channel mosfet 546.