Dynalyzer – High Voltage Unit
OPERATION MANUAL
14
Operation
This unit is designed to operate with three possible read-out devices:
1. A suitable oscilloscope
2. The Dynalyzer II or III Digital Display
3. A digital voltmeter
All measurements can be made with the optional Digital Display Unit and most measurements can
be made with the oscilloscope (requiring interpretation contained in the Measurements with
Suitable RMS Voltmeter section of this manual). In addition, some measurements can be made
with a voltmeter readout.
CAUTION:
As 5 foot long high voltage cables are normally used to connect the Dynalyzer III High
Voltage Unit to the x-ray tube (necessitating that the HVU be placed on the table) the
possibility exists that the HVU may be inadvertently left in the primary beam. If this
occurs, the SF
6
gas used to insulate the internal components in the tank section of the
HVU may become sufficiently ionized to cause gross measurement errors, e.g., 20 to
30 kV. In order to guard against this possibility, the user must be careful to angle the
tube away from the HVU or close the collimator shutters.
Readout Oscilloscope
a. Measurement of kVp and exposure duration for both single-phase and three-phase machines
may be read directly from the oscilloscope trace.
b. Current measurements for radiographic exposures may be read from the oscilloscope trace.
Measurement procedure for kVp and Exposure Time Using Oscilloscope
a. Connect the oscilloscope to the High Voltage Unit as shown in Figure 7.
b. Adjust the gain of the preamp of the oscilloscope for 2-volts per division.
c. Adjust the horizontal time base for 10 milliseconds per division.
d. Connect the scope to the Anode + Cathode output or to the separate outputs if switching
between individual and summed outputs is desired. The exact switching will vary due to
differences in x-ray high-voltage generator controllers. Refer to specific instructions for the
model being calibrated.
Anode + Cathode Output
It is often necessary to view kVp and mA on the same dual trace oscilloscope. As this unit
features a composite kV output with a separate BNC connector, the Anode + Cathode kV
