Dr. Bob

Nanocrystalline Silver Alloy Contact Finishes in Electronic Applications

Dr. Bob reviews two recently published papers to draw conclusions on the possible use of nanocrystalline silver alloy contact finishes in electronic applications. In my previous article, in which I mentioned two recent papers* on the nanocrystalline silver alloys of silver-tungsten (AgW) and silver-palladium (AgPd) and their use as contact finishes, I highlighted the potential benefits these alloysRead More

Nanocrystalline Silver Contact Platings

New silver alloys address the issues of durability and conductivity through a fundamental difference in crystalline structure. Dr. Bob takes a closer look at nanocrystalline silver contact platings.   Two papers* were published last year that introduced nanocrystalline silver alloy contact platings – one a silver-palladium alloy and the other silver-tungsten. Both papers cite theRead More

Dr. Bob on Gold Flash Contact Finishes (and Max Peel)

To honor his former colleague Max Peel, who passed away in April, Dr. Bob discusses gold flash contact finishes and the warning that is Peel’s Law. This article will eventually be about gold flash contact finishes, but it begins with a few words about my colleague Max Peel. Max passed away on April 16 ofRead More

Corrosion and Contact Resistance

Dr. Bob follows up his recent article on connector contact lubricants with a look at connector corrosion and contact resistance. While I was making the final edits to my recent Connector Supplier article on connector contact lubricants, I looked at the figure in that article, which showed the structure of the contact interface on a microscale,Read More

Connector Contact Lubricants

Connector contact lubricants can reduce mating forces and contact wear, and there are lubricants to do just that. But the real goal is to get more than just friction/wear reduction from a lubricant. For many of us the first thing that comes to mind when the word “lubricant” comes up is “slippery stuff,” motor oil,Read More

Stress Relaxation II – Effects on Performance

Stress Relaxation II Effects on Performance The February feature, Stress Relaxation I: Mechanisms, Materials and Temperature, described the mechanism of stress relaxation as repositioning of atoms to reduce localized stresses and the resulting loss in contact force, and reduction in mechanical stability. Now, let’s see how that repositioning and force reduction can affect connector performanceRead More

Stress Relaxation I – Mechanisms, Materials and Temperature

Stress Relaxation I Mechanisms, Materials and Temperature In the metallurgical world, stress relaxation is defined as a time-dependent loss in stress at constant strain. OK, you may ask, but what does that have to do with connectors? It’s all about contact force. The contact normal force is a critical design parameter for connectors, because theRead More

Hertz Stress II – Achieving the Right Degree of Resistance

Hertz Stress II Achieving the Right Degree of Resistance In the first Hertz stress article, I cited two limitations of Hertz stress as a connector design parameter. First, a Hertz stress value can be realized by different combinations of contact force and contact geometry, each producing different values of connector contact resistance. Second, variations inRead More

Hertz Stress as a Connector Design Parameter

Dr. Bob on Hertz Stress as a Connector Design Parameter I was looking for some information in my files a few weeks ago, when I came across a folder entitled “Hertz Stress.” My mind leapt back 20 years as I recalled discussions that the concept had raised at that time. Using Hertz stress as aRead More

Power Distribution II – Signal Contacts in Parallel

Power Distribution II Signal Contacts in Parallel This is the final article in our series about the distribution of current in power applications. In the previous article in this series, the topic was distribution of current using dedicated high current, several tens of amperes, contacts.  This article will address the use of multiple signal—low current,Read More

Power Contacts and Connectors Part 1 – Power Distribution

Power Contacts and Connectors Part 1: Power Distribution Today, there are three different approaches to power distribution in connectors, particularly, on current distribution. They include individual high-current contacts, multiple low-current contacts in parallel, and hybrids, which use both approaches in the same housing. Each approach has its advantages and limitations. Let’s begin with high-current contacts,Read More

Power Contacts/Connectors Part III – Current Rating 2

Power Contacts/Connectors Part III: Current Rating 2 This week, let’s examine the current rating test program, which includes the measurements to be made and the conditioning and exposures to be applied in connector testing. Figure 1 includes an example program. A program of this general nature is under consideration in ECA CE-2.0 National Connector andRead More

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