Hello everyone, and welcome back to another weekly design challenge summary. This week is a little different as I am covering the fifth, sixth, and seventh weeks of the Experimenting with Polymer Capacitors Design Challenge, and while some progress has been made over the past three weeks, not enough updates were posted to justify a separate post for each week. Before we get to the good stuff, let’s take a few moments to learn more about this challenge, its challengers, and what hardware is being featured. 



Experimenting with Polymer Capacitors Design Challenge


About The Challenge


The Experimenting with Polymer Capacitors Design Challenge is a new type of challenge for 2019, this challenge is a hands-on competition that everyone in the community can participate in. Instead of requiring a participant to produce a full prototype, project, or original circuit design, we decided that we'd give our members the opportunity in this competition to experiment, test, breadboard, or just play around with Polymer Capacitors, and then tell us about their experiments, and what they learned about Polymers Capacitors in some blog postings.


While only nine sponsored challengers were chosen to receive a free polymer capacitor kit, entering the challenge is not limited to just those nine community members. Anyone can join the competition by including at least one of the kit's polymer capacitors in his/her experiments



The Official Kit


Nine Challengers received a discrete component kit that included several different types of capacitors that can be used to experiment with. As the list is quite long, I am not going to post it here. If you are interested in purchasing the kit for yourself, please visit this link.



The Prizes



To learn more about the prizes, head over to this page. (https://www.element14.com/community/docs/DOC-92091/l/experimenting-with-polymer-capacitors-about-the-competition)



The Past Week In Review


Over the past few weeks, June 9th- June 29th, we have had a total of four updates posted across three projects, hence my lack of updates. This week I will feature a post from each project that was updated, but before I get to that, let's take a look at which projects were updated. 




This Week’s Top Updates


COMPACT  - Experimenting with Polymer Capacitors Blog  #3 - More than you expect!



As his experiments with polymer capacitors draw to a close, COMPACT took a little more time to check out a series of polymer capacitors from WURTH Electronics that are a direct replacement aging electrolytic capacitors that have lost their spec. “This challenge is an investigation about the viability of polymer capacitors and their use with vintage electronics,” he wrote. “With the Panasonic SMT capacitor portion completed, I was still looking for viable Polymer capacitors in through-hole sizes and packaging.” He tested the WURTH capacitors against a couple of electrolytic capacitors that were well past their prime, and the results were as expected. The new polymer capacitors were well within spec to replace the aging units.


“This winds up my adventures into Polymer Capacitors. I hope you've enjoyed the adventure. Polymer Capacitors are a truly viable choice provided that the specified parameters are compatible,” he concluded. “It is not just capacitance alone determining the choice of the component.  There are a plethora of parameters to consider for selecting the correct capacitor type and value for design quality, stability, longevity and most importantly - SAFETY."



Neuromodulator  - Experimenting with Polymer Capacitors Blog  #1 - Introduction and methods



Neuromodulator kicked off his experiments with Polymer Capacitors by breaking out the hot glue gun and waterproofing the bottom of some polymer capacitors he planned to test. This was to waterproof them so that they could be tested for capacitance while being immersed in a bowl of warm water. “I soldered cables into the capacitors and then waterproofed them with hot glue. The quality of the waterproofing was tested by checking if the DMM measured a capacitance changed after immersion into water (oil would have been much better but the water was what I had at hand)," he wrote. “ As the Keithley DMM6500 measures the capacitance by measuring the voltage slope while supplying a constant current to the capacitor, a parallel resistor (water making contact to both terminals) would have the effect of making the DMM display a higher capacitance. The hot glue waterproofing appeared to work well as in none of the 3 capacitors I noticed any increase of the measured capacitance after immersion.” Testing was done with a Keithley DMM, and a MyDAQ. He also wrote a short python script to help with data acquisition via the MyDAQ which has it's own built-in DMM. To learn about his testing methods, and a weird anomaly that he experienced with current leakage based on water temperature, click on the link above.



Michael Kellett  - Experimenting with Polymer Capacitors Blog  #1 - Capacitor Leakage Current over Temperature



After reading Neuromodulator’s experience with current leakage based on temperature, Michael Kellett was inspired to do some testing of his own. In his first post, he used an Espec SH262 Benchtop Temperature and Humidity chamber along with a  Keysight 34972A34972A Data Acquisition system to somewhat replicate Neuromodulator’s testing environment. “Each capacitor was connected in series with a 1000R metal film resistor and the 34972A34972A, on the 10mV range, was used to measure the voltage across the resistor from which the current can be determined. A set of 8 measurements was taken every 20 seconds. The whole setup was controlled by a PC via Ethernet,” Michael wrote. “I wanted to change the temperature as quickly as possible to investigate the effect of the rate of change of temperature so I set the ramp rate of the SH262 to 3  degrees/minute, which it can just manage when heating and not quite manage when cooling. The temperature was changed from -20C to +80C with 2 hours dwell at each extreme. I ran the experiment for 10 complete cycles (50 hours).” Once again this is one of those updates that are hard to summarize in a few short paragraphs, so I highly suggest heading over to the full post at the link above.




That is going to wrap up this weeks coverage of the Experimenting with Polymer Capacitors Design Challenge. If you have not yet done so, please take a moment and check out all of this week's updates, and show our challengers some love in the comments section of each update post. Check back next week for another weekly design challenge summary.