Category Archives: electrolytic capacitor

Replace Old Electrolytics? Not So Fast… Maybe

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[CuriousMarc] was restoring an old Model 19 TeleType. The design for these dates back to the 1930s, and they are built like tanks (well, except for the ones built during the war with parts using cheaper metals like zinc). Along the way, he restored a hefty tube-based power supply that had two very large electrolytic capacitors. These dated from the 1950s, and common wisdom says you should always replace old electrolytics because they don’t age well and could damage the assembly if powered up. [Marc] didn’t agree with common wisdom, and he made a video to defend his assertion which …read more

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Soda Bicarb Diode Steering Circuit For 7-Segment Display

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[Hales] has been on a mission for a while to make his own diodes and put them to use and now he’s succeeded with diodes made of sodium bicarbonate and water, aluminum tape and soldered copper. By combining 49 of them he’s put together a soda bicarb diode steering circuit for a 7-segment display capable of showing the digits 0 to 9.

He takes the idea for his diode from electrolytic capacitors. A simple DIY electrolytic capacitor has an aluminum sheet immersed in a liquid electrolyte. The aluminum and the conductive electrolyte are the two capacitor plates. The dielectric is …read more

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Repairing 14 Tektronix TLA5202 Logic Analyzers

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[Matthew D’Asaro] was recently entrusted with an entire classroom fleet of fourteen broken Tektronix TLA5202 logic analyzers — a pile of equipment that once was worth hundreds of thousands of dollars. His task: Fixing them. He fixed them all, and on the way documented a number of common failure points in these old but still great devices.

[Matthew] found that Tektronix’s portion of the electronics took the ravages of time and classroom use quite well, only the embedded desktop PCs inside the machines simply weren’t built for the ten-year. Some of the hard-drives had to be replaced, but most units …read more

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History Of The Capacitor – The Modern Era

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The pioneering years in the history of capacitors was a time when capacitors were used primarily for gaining an early understanding of electricity, predating the discovery even of the electron. It was also a time for doing parlor demonstrations, such as having a line of people holding hands and discharging a capacitor through them. The modern era of capacitors begins in the late 1800s with the dawning of the age of the practical application of electricity, requiring reliable capacitors with specific properties.

Leyden Jars

One such practical use was in Marconi’s wireless spark-gap transmitters starting just before 1900 and into …read more

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