Bio-Rad Gene Pulser Xcell™ Electroporation Systems - Manual (Page 46)

3.9.2 Calibration and Measurement of Capacitors in the CE Module
Because electrolytic capacitors change value slowly over time, to keep the instrument within its original
specifications, the capacitors should be calibrated approximately every one to three months or whenever
there is concern about the accuracy of the capacitors. The Capacitor Measurement function gives the
user a more accurate determination of the capacitor values in the unit by making a measurement of the
capacitors in the units. Capacitor calibration and measurement may be performed as follows.
• Unplug the ShockPod cables from the Gene Pulser Xcell. Connect the CE Module to the Gene
Pulser Xcell.
• From the Measurements screen, press 2 or use the Up and Down Arrow keys to highlight
“Capacitor”, then press Enter to display the Capacitor Measurement screen (Figure 3.33).
• To calibrate the capacitors, press the decimal point (.) on the alpha-numeric keypad. The Gene
Pulser Xcell main unit will begin calibrating the capacitors in both the CE Module and the Gene
Pulser Xcell main unit. Calibration will take about two minutes. At the completion of the test,
12 numbers will be displayed at the bottom of the screen. The numbers on the top row and the first
three on the bottom row are the actual values of the capacitors in the CE Module. These capacitors
are used in combination to set the capacitance in the exponential decay and time constant modes.
When pulsing using the low voltage circuit in square wave mode, all of the capacitors from the CE
Module are used together; when pulsing using the high voltage circuit in square wave mode, the
50 uF capacitor in the Gene Pulser Xcell main unit is used.
• To measure a specific capacitance, with the Capacitor Measurement screen on the LCD, use the
alpha-numeric keypad to type in a capacitance value to be measured. Alternatively, use the Right
and Left Arrow keys to increase or decrease, respectively, the capacitance values. Press Enter,
then press Pulse. The actual capacitance value appears on the Measured Capacitance line. (No
sample should be in place and no pulse occurs during this process.)
Capacitor Measurement Screen
Fig. 3.33. Capacitor Measurement screen.
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C a p a c i t o r m e a s u r e m e n t
C a p a c i t a n c e ( u F ) x x x x
M e a s u r e d c a p a c i t a n c e ( u F ) x x x x