| Patent Number |
Title Of Patent |
Date Issued |
| D308832 |
Electrical test instrument |
June 26, 1990 |
|
| 5084703 |
Precision digital-to-analog converter |
January 28, 1992 |
| A digital-to-analog converter is disclosed which employs a ladder configuration comprising a series of R1-R2-R3 stages in which resistors R2 and R3 are selected so that mathematically the combined resistance of R2 in parallel with R3 is equal to twice the resistance of R1. The resistance |
| 5063353 |
Method for accurate measurement of transmission line impedance by correcting gross impedance for |
November 5, 1991 |
| A method for measuring the impedance of a transmission line. The length and D.C. loop resistance of the line are measured. A pulse is transmitted along the line, the pulse having a duration greater than the time required for it to propogate from its source to the end of the transmission |
| 5057783 |
Automatic impedance matching |
October 15, 1991 |
| Apparatus (1) for performing an electrical test on a cable (3) used in local area networks (LAN's). A source (37) produces electrical signals transmitted through the cable. A resistance circuit (43) is interposed between the source and the cable. The amount of resistance interposed by |
| 4808930 |
Technique of compensating for capacitive effects in conductivity measurements |
February 28, 1989 |
| Improved accuracy in solution conductivity or resistivity measurment uses a center-sampling technique in which an AC drive is applied to a conductivity cell and the conductivity cell voltage is sampled during a predetermined time interval in the center of a half cycle drive waveform. |
| 4776942 |
Electrochemical sensor |
October 11, 1988 |
| An improved sensor for dissolved oxygen measurement comprising a body having an electrolyte reservoir and electrolyte contained therein and an opening for communication between the exterior of the body and the reservoir and an anode and cathode concentrically disposed in the body adj |
| 4742708 |
Apparatus for electrochemical sensor calibration |
May 10, 1988 |
| Apparatus for removably connecting a calibrating gas chamber to the body of an electrochemical sensor consisting of corresponding members carried by the sensor and the gas chamber, each member defining a contact surface that cooperates with the contact surface of the corresponding member |
| 4741198 |
Thermal conductivity detector assembly |
May 3, 1988 |
| The present invention relates to a gas chromatography assembly comprising a high mass, thermally conductive body provided with at least one cell in which is disposed a resistance filament for the detection of a sample gas. Lines are provided for communication between the cell and sample |
| 4707244 |
Solid state sensor element |
November 17, 1987 |
| A solid state sensing element comprising a nonporous, structurally stable, electrically insulating substrate on which is disposed spaced apart pairs of electrodes for contact with moisture. A hygroscopic electrolytic material is located in close proximity to the electrodes as by coating |
| 4691168 |
High purity water calibrating device |
September 1, 1987 |
| Apparatus for calibrating a conductivity instrument having a conductivity cell and a conductivity measuring instrument operatively associated with the conductivity cell, includes a conduit for supplying high purity water to be measured; a first flow line for supplying the high purity wat |
| 4655900 |
Method for treating electrodes and improved electrochemical cell |
April 7, 1987 |
| An improved electrochemical cell is described which comprises at least one electrode having increased signal strength achieved by treating at least the working surface of the electrode with a coating of a polytetrafluoroethylene and a catalyst metal selected from the group consisting |
| 4650562 |
Reference electrode device |
March 17, 1987 |
| A normal pH sensitive glass electrode is deactivated by exposure to thermal treatments at relatively high temperatures of approximately 190.degree. C. for predetermined periods of time until the nominal electrode sensitivity is reduced to very low levels such that the output potentials o |
| 4633164 |
Microprocessor controlled constant current circuit |
December 30, 1986 |
| Apparatus for generating a constant current, comprising a storage device for storing a voltage corresponding to the constant current, the storage device including a resistor-capacitor filter and having an input and an output; a Zener diode for supplying a constant voltage; a first high |
| 4618771 |
Non-dispersive infrared analyzer having improved infrared source and detecting assemblies |
October 21, 1986 |
| An improved non-dispersive infrared analyzer. The analyzer includes an improved source assembly having a reflecting element with a concave annular reflecting surface, and a circular heating element which is located substantially at the focal region of the reflective surface. The anal |
| 4614846 |
Interlocked push button switch assembly |
September 30, 1986 |
| A push button switch assembly comprising a plurality of push button switch actuators includes a flexible, unstretchable electrically non-conductive belt for permitting only one of the push button switch actuators at a time to be in its activated position while the remaining switch actuat |
| 4605984 |
Static control strap |
August 12, 1986 |
| A grounding device for connecting the body of a person to a ground point to drain off electrostatic charge from the body of the person. The device includes a conductive band worn on the wrist of the user, a connecting cable and sensing and indicating circuitry for verifying the electrica |
| 4602162 |
Monitoring port for ultraviolet water purification systems |
July 22, 1986 |
| A monitoring port for use in measuring the intensity of the ultraviolet radiation within an ultraviolet water purification system. A UV transparent transmitting member is sealably mounted for inward, outward, and rotational movement movement with respect to a UV lamp. A locking arran |
| 4575410 |
Solid state electrode system for measuring pH |
March 11, 1986 |
| An improved solid state electrode system for measuring the pH of fluids at temperatures as high or even higher than that corresponding to the critical point of water (374.2.degree. C.). A stabilized metal oxide based ceramic member having a predetermined thickness is coupled to a first |
