5 volt supply., Note that since both outputs 1" />
 
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5 years ago

Applying the pulsed ion chamber methodology to full range reactor ...

Applying the pulsed ion chamber methodology to full range reactor ...

(•-: "1 CATHODE PIC

(•-: "1 CATHODE PIC EQUIVALENT CIRCUIT '""~"T V i \ > i i 1 ... ^& \ v(tj 34

lose, across pins 10 and 11 and resistive load between pin 9 and >5 volt supply., Note that since both outputs 1 and 6 appear simultaneously, utilizing the positive rather than the negative output to trigger 1 next 741215 at inputs 3 and/or 4, results in it being triggered at the end of the input pulse. Thus its output is delayed by the width of the input pulse. This fact was often used in the design of the system now described. The pulsing-sampling rate of the entire computer based PIC system is control led, within limits, by the SN555 timing IC. The falling edge of its positive output, is used to trigger IC-2, an SN74121 monostable multi- vibrator. (Note all the remaining designated ICs art SN74121.) IC-2 provides the necessary variable Lime delay between the application of HV and triggering of the cathode impedance rircuitry. The trailing edge of the positive output pulse of IC-2, whose width is controlled by P-2, serves to trigger IC-3. The positive output of IC-3 is then fed into the driving transistor Q-l , which inverts the pulse and drives the high voltage transistors Q-2 through 0-5, rapidly to their low impedance state, thus applying voltage to the outer shell of the chamber. The leading edge of the negative output of IC-2 triggers IC-4. Note that this occurs sometime before the high voltage is applied. IC-4 provides the necessary variable time of occurrence required so that the pulse which forces the cathode switching transistor into a high impedance state may be positioned to occur immediately after the chamber has been charged to its lull potential. The trailing edge of the positive output pulse of IC-4, whose width is controlled by P-4, serves to trigger IC-5. The positive output of IC-5 is then fed into the driving transistors Q-6 the