phone: (215) 947-2500 fax: (215) 947-7464 e-mail: [email protected] web site: www.televac.com
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CHAPTER 2
(cont.)
TELEVAC
Safety Instructions (cont.)
`
Principles of Sensor Operation
Double Inverted Magnetron
Cold Cathode Gauge
The cold cathode gauge is a high vacuum sensor that measures pressure by ionizing the residual gases
in a magnetron discharge. The body of the gauge serves as a cathode, and is at ground potential. The
anode operates at voltages up to 4000 volts. The permanent magnet traps electrons in the gauge to
sustain the discharge at very low pressure. This gauge is sensitive to gas type. Because of the relative
ruggedness of this gauge and since it has no filament to burn out, it is often used in applications where
hot cathode gauges are not reliable.
Objects and Liquid Entry – Never push objects of any kind into this product through
openings as they may touch dangerous voltage points or short out parts that could result in
a fire or electric shock. Be careful not to spill liquid of any kind onto the products.
Do not substitute parts or modify instrument.
Because of the danger on introducing additional hazards, do not install substitute parts or
perform any unauthorized modifications to the product. Return the product to Televac for
service and repair to ensure that safety features are maintained. Do not use this product
if it has unauthorized modifications.
CHAPTER 3
