A Capacitive Fringing Field Sensor Design for Moisture Measurement Based on Printed Circuit Board Technology

2012 ◽  
Vol 61 (4) ◽  
pp. 1105-1112 ◽  
Author(s):  
Robert Neal Dean ◽  
Aditi Kiran Rane ◽  
Michael E. Baginski ◽  
Jonathan Richard ◽  
Zane Hartzog ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Sensor Design ◽  
Moisture Measurement ◽  
Printed Circuit ◽  
Fringing Field ◽  
Field Sensor

Capacitive Fringing Field Moisture Sensors Implemented in Flexible Printed Circuit Board Technology

2014 ◽  
Vol 11 (3) ◽  
pp. 122-127 ◽  
Author(s):  
Robert N. Dean ◽  
Michael C. Hamilton ◽  
Michael E. Baginski
Keyword(s):  
Dielectric Constant ◽  
Flexible Electronics ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Radius Of Curvature ◽  
Printed Circuit ◽  
Sensor Performance ◽  
Fringing Field ◽  
Flexible Printed Circuit ◽  
Cu Foil

Capacitive fringing field sensors are often used in applications where moisture is detected, since the dielectric constant of liquid water is approximately 80 times greater than the dielectric constant of air. Most of these sensors, however, are realized using rigid substrates. Some applications would benefit from using a flexible capacitive fringing field sensor that could be conformally mounted on a nonplanar surface. Flexible printed circuit board technology is a mature commercially available process for manufacturing flexible electronics. This same technology can also be used to realize flexible fringing field moisture sensors where the patterned Cu foil is used for the electrodes and the soldermask coating electrically insulates the electrodes from being electrically shorted by moisture in the detection environment. Sensors were designed and characterized through flat and bending tests in air and in water. The tests demonstrated that bending a sensor over a radius of curvature as small as 13.7 mm had no measurable impact on sensor performance in air or in water. The sensors achieved a 3:1 increase in capacitance when immersed in water compared with in air.

An Integrated Sensor for Detecting Moisture Ingress in Printed Circuit Board Assemblies

2016 ◽  
Vol 2016 (1) ◽  
pp. 000568-000571
Author(s):  
Robert N. Dean ◽  
Nathan B. Loden ◽  
Curtis J. Hartley ◽  
Jeffery D. Craven
Keyword(s):  
Printed Circuit Board ◽  
Prolonged Exposure ◽  
Relaxation Oscillator ◽  
Circuit Board ◽  
Printed Circuit Board Assembly ◽  
Integrated Sensor ◽  
Interface Circuit ◽  
Printed Circuit ◽  
Circuit Board Assembly ◽  
Fringing Field

Abstract Numerous applications exist where electronics must operate reliably in moist environments, and often for long periods of time. In these environments, the circuit board assemblies may experience moisture ingress, which can deleteriously affect the operation and life span of these systems. Detecting moisture ingress is therefore useful for improving system design, assembly techniques, packaging technologies and maintenance scheduling. Capacitive fringing field sensors are useful for measuring the moisture content of materials. Therefore, a capacitive fringing field sensor, implemented in printed circuit board technology with a CMOS relaxation oscillator interface circuit, is proposed for detecting moisture ingress into the printed circuit board assembly. A set of instrumented sensors was designed, fabricated and tested. The results demonstrated that when the test articles experienced prolonged exposure to moisture, the instrumented sensors experienced an 18.42% change in output value, indicating a satisfactory sensitivity to moisture ingress.

scholarly journals A Technique for Detecting Moisture Absorption in Printed Circuit Boards

2020 ◽  
Vol 17 (1) ◽  
pp. 28-33
Author(s):  
Jeffery D. Craven ◽  
Ariel R. Oldag ◽  
Robert N. Dean
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Moisture Absorption ◽  
Low Cost ◽  
Circuit Board ◽  
Sensor Technology ◽  
Circuit Boards ◽  
Liquid Form ◽  
Printed Circuit ◽  
Fringing Field

Abstract Most circuit boards operate in environments that have the potential to be exposed to moisture, either in vapor or liquid form. Because low-cost circuit boards can readily absorb moisture, this can lead to performance issues, reliability issues, and even catastrophic failure. However, it is difficult to detect if moisture absorption has occurred before the circuit board suffers a complete failure. To alleviate this issue, a fringing field capacitor was implemented in printed circuit board (PCB) technology and used to detect the absorption of moisture in the circuit board through the accompanying increase in capacitance. Prototype sensors were fabricated and immersed for 42 d, demonstrating an increase in capacitance of between 14% and 29%. This sensor technology can easily be added to circuit board designs because they use the standard materials and fabrication processes used in commercial PCB construction.

Characteristics of Radiated Emission from a Printed Circuit Board with a Slit

2012 ◽  
Vol 132 (6) ◽  
pp. 404-410 ◽  
Author(s):  
Kenichi Nakayama ◽  
Kenichi Kagoshima ◽  
Shigeki Takeda
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Printed Circuit ◽  
Radiated Emission

Confirming the Signal Integrity in Transmission of Digital Signals on Microstrip Straight Circuits via the Eye Diagrams

2014 ◽  
Vol 5 (1) ◽  
pp. 737-741
Author(s):  
Alejandro Dueñas Jiménez ◽  
Francisco Jiménez Hernández
Keyword(s):  
Integrated Circuits ◽  
Printed Circuit Board ◽  
Signal Integrity ◽  
High Volume ◽  
Information Storage ◽  
Circuit Board ◽  
Electromagnetic Simulation ◽  
Electronic Systems ◽  
Digital Signals ◽  
Printed Circuit

Because of the high volume of processing, transmission, and information storage, electronic systems presently requires faster clock speeds tosynchronizethe integrated circuits. Presently the “speeds” on the connections of a printed circuit board (PCB) are in the order of the GHz. At these frequencies the behavior of the interconnects are more like that of a transmission line, and hence distortion, delay, and phase shift- effects caused by phenomena like cross talk, ringing and over shot are present and may be undesirable for the performance of a circuit or system.Some of these phrases were extracted from the chapter eight of book “2-D Electromagnetic Simulation of Passive Microstrip Circuits” from the corresponding author of this paper.

Root Cause Analysis of a Connector Time-Delayed Fracture

2015 ◽  
Author(s):  
Prabjit Singh ◽  
Ying Yu ◽  
Robert E. Davis
Keyword(s):  
Printed Circuit Board ◽  
Ceramic Substrate ◽  
Circuit Board ◽  
Delayed Fracture ◽  
Ceramic Substrates ◽  
Printed Circuit ◽  
Root Cause ◽  
Chip Carrier ◽  
Electrical Connections ◽  
Grain Boundary Grooves

Abstract A land-grid array connector, electrically connecting an array of plated contact pads on a ceramic substrate chip carrier to plated contact pads on a printed circuit board (PCB), failed in a year after assembly due to time-delayed fracture of multiple C-shaped spring connectors. The land-grid-array connectors analyzed had arrays of connectors consisting of gold on nickel plated Be-Cu C-shaped springs in compression that made electrical connections between the pads on the ceramic substrates and the PCBs. Metallography, fractography and surface analyses revealed the root cause of the C-spring connector fracture to be plating solutions trapped in deep grain boundary grooves etched into the C-spring connectors during the pre-plating cleaning operation. The stress necessary for the stress corrosion cracking mechanism was provided by the C-spring connectors, in the land-grid array, being compressed between the ceramic substrate and the printed circuit board.

Application of Lock-in Thermography on PCB for Fault Localization and Validation of Failure Mechanism Due to External Discrete Component Variation

2010 ◽  
Author(s):  
William Ng ◽  
Kevin Weaver ◽  
Zachary Gemmill ◽  
Herve Deslandes ◽  
Rudolf Schlangen
Keyword(s):  
Failure Mechanism ◽  
Integrated Circuit ◽  
Printed Circuit Board ◽  
Hot Spot ◽  
Circuit Board ◽  
Discrete Component ◽  
Printed Circuit ◽  
Thermal Signature ◽  
Lock In

Abstract This paper demonstrates the use of a real time lock-in thermography (LIT) system to non-destructively characterize thermal events prior to the failing of an integrated circuit (IC) device. A case study using a packaged IC mounted on printed circuit board (PCB) is presented. The result validated the failing model by observing the thermal signature on the package. Subsequent analysis from the backside of the IC identified a hot spot in internal circuitry sensitive to varying value of external discrete component (inductor) on PCB.

Temperature and Humidity Dependent Reliability Analysis of RGB LED Chips

2006 ◽  
Author(s):  
Jun-Xian Fu ◽  
Shukri Souri ◽  
James S. Harris
Keyword(s):  
Reliability Analysis ◽  
Printed Circuit Board ◽  
Light Emitting Diode ◽  
Circuit Board ◽  
Light Emitting ◽  
Printed Circuit ◽  
Root Cause ◽  
Micro Cracks ◽  
Temperature And Humidity

Abstract Temperature and humidity dependent reliability analysis was performed based on a case study involving an indicator printed-circuit board with surface-mounted multiple-die red, green and blue light-emitting diode chips. Reported intermittent failures were investigated and the root cause was attributed to a non-optimized reflow process that resulted in micro-cracks and delaminations within the molding resin of the chips.

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