Teledyne DNV-33D instruction manual Operating Principle, 1.0SPECIFICATIONS, Section

SECTION II

Operating Principle

The operation of Hastings vacuum gauges uses a patented noble metal thermopile circuit. The hot junctions of the thermopile are heated directly by an AC current while an equal number of cold junctions are kept at ambient temperature by heavy mounting studs. Thus a DC voltage is then generated between the hot and cold junctions. As the pressure decreases, the lowering of the thermal conductivity of the gas surrounding the hot junction tends to increase the tempera- ture of the hot junctions, thus increasing the output of the thermopile. This change in output is then amplified, linearized, and calibrated as a function of pressure.

1.0SPECIFICATIONS

Indicator Model		DNV-33D
Case Dimension		Front Panel 96mm SQ. Depth 10 ¾”
Gauge Tube Type		DV-33D-1, DV-33D-2, DV-33D-3*
Gauge Tube Shell		Welded stainless steel shell
Overpressure		1500 PSIG max.
Panel Cut-out		3-1/16” (77.5 mm) H x 3-5/8” (92mm)W
Range		1-1000 mTorr
Readout		Digital Meter
Power		115 VAC, less than 6 watts
Outputs		Linear 0-1 VDC analog @ 4 ma. Max.
Calibration		Calibrated for air or nitrogen
*Dash number Defines System Fitting Differences:
-1	Weld Fitting
-2	Cajon #SS-4 VCR Male Gland
-3	Cajon #SS-4 VCR Female Gland

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