UBM Tech
UBM Tech

Glen Chenier

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's contributions
  • 03.25.2014
  • Give me those old-tyme displays
  • "My parts stash includes some incandescent seven-segment displays; but I've never seen them used in an actual product" One of the products in which these were used was a Heathkit Digital (as opposed to rotating disc with flashing neon lamp) Marine Depth Sounder, forgot the model number. IIRC the 8th segment was a little X of incandescent wires to form the decimal point. Can't recall if they were used in any other Heathkit products.
  • 03.18.2014
  • Bouncing short beats clean one for power system testing
  • Oh, forgot to mention 10GSa and 1GHz BW each channel :^} But that Pico scope looks very interesting, and would have served nicely for this purpose. Plus it has current probe options, when doing the blogged power debugging the companion 4 ch scope was a LeCroy with a couple current probes. By printing the 2 plots on paper triggered from the same event, juxtapositioned vertically and sized to match horizontal timebase graticules, it sort of resembled an 8 channel scope.
  • 01.10.2014
  • How did you learn PCB layout?
  • College 40 years ago touched briefly on this subject - red and blue tape on transparent film. That was it. But over the years I learned, and sat with the layout tool operators for days on end getting them to place the copper and layer thickness exactly the way I wanted. This was the result of one overly-zealous layout guy that worked over the weekend and presented me with a totally botched job Monday morning. Never happened again. Recently learned the basics of KiCad for my latest product. It's not rocket science - operating the CAD tool is one thing, but knowing where to place the copper is a whole different skill. Unfortunately most management types do not comprehend that.
  • 02.04.2014
  • The last half-century: Wirewound resistors Part two
  • What an interesting and informative story! Will never look at resistors the same way again. Would be nice to see more related blogs about the trials and tribulations of developing other types of parts, there must be those out there with stories to tell...
  • 09.17.2013
  • Resistor combinations: How many values using 1kohm resistors?
  • @xienwolf, Right, you are an astute reader. Noted these 2 errors in previous comments: "Oops! I goofed on the group of 5 lower right corner - is 500 ohms, not 333 ohms. Sept 17, 2013 4:41 PM EDT" "Also there is a 2nd goof in the groupings of 5. Can you spot it? Sept 17, 2013 4:46 PM EDT"
  • 12.22.2013
  • A method of demonstrating transmission-line behavior on a dual-channel oscilloscope
  • Yor, try this experiment: Drive only one speaker with a tone, say about 400 Hz. Plug one ear so that only one ear is functional. Then move slowly around the room and note how many places the sound weakens or disappears, you will have to move your head in all 3 dimensions to find the perfect nulls. The standing wave nulls are caused by waves reflecting off the walls and furniture. They change location depending on wavelength. When listening to stereo music, two speakers, two ears, and many frequencies at the same time make these nulls difficult to detect.