Kyle B

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Kyle B

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  • 03.22.2017
  • Der alte battery
  • Hi John Per my contact with battery manufacturers, they won't give data beyond the graphs because they can't predict battery performance at very very low discharge rates. While reasonable assumptions are made, you actually are oversimplifying the issue. The drains you're measuring are of similar magnitude to the battery's self discharge, so that can't be ignored. Your testing doesn't measure this and doesn't take it into account. You're extrapolating past the valid data on the battery curves. In the limit, at 'infinite resistance' the curves would predict 'infinite lifetime'. That can't be true, right? Take a closer look at the curve data. The 'mA-hr' rating only holds true at one specific drain rate. The capacity of the cell varies with discharge rate. The bar graphs and charts in the article infer exactly this, but your text never does, so thought I'd mention it. Easy to overlook. Also - Your DMM isn't going to be able to measure the current of your alarm clock. It's not fast enough, you'll miss the 1Hz spikes. Use a current-sense resistor and an oscilloscope, or a DMM with an RC network connected across it and measure voltage instead of a current. It's also interesting to note that an el-cheapo carbon-zinc ("Heavy Duty") cell will work just about as good as your expensive alkaline in this application. Alkalines are great for high-current applications because they can diffuse gas off their electrodes faster than C-Zn. This is why heating up a battery can bring it back to life temporarily - It increases the diffusion rate. Use 9V C-Zn in your smoke detectors... They'll last a year, just like an alkaline 9V, at about 1/5th the cost. BTW - We make our current-sense probes out of slices of double-sided PCB material. Way easier than your design. Your vocabulary is good ... They're 'cells' not 'batteries'. Kudos to you for getting the nomenclature correct!
  • 12.26.2016
  • Underwater Navy drones: Can electronics deter illegal seizures and technology theft?
  • Every military drone should have the equivalent of about 10 sticks of TNT embedded. Forget about just burning the IC's. Turn the wrong screw and the drone, and everybody within 20 feet, turns to dust. Not only do you discourage tampering, you might also get to take out some of the enemies best brains & technical facilities in the process.
  • 10.26.2016
  • 1st Hoover Dam electric generator goes into full operation, October 26, 1936
  • Your protest doesn't make sense. Providing a statement that the dam produces a certain amount of energy each year is perfectly reasonable. It's the same units that consumers get charge for. It's like saying a farmer sells a certain amount of tomatoes each year. if you want it in terms of average power produced, that could be inferred from the context (presuming one knows how many hours are in a year...). I guess I'm missing your point --- What exactly is wrong with giving the value in KW-Hr?
  • 02.23.2016
  • GPS-based mood sensing could save lives
  • WTH? Do we not have enough snooping into our private lives already??? This is a horrible idea. It's nobody's business where I go or when. I'm seriously considering sticking my phone in a metal sack when I drive around.
  • 02.22.2016
  • Primary colors
  • - You may 'trick your eye' into thinking that you see 'white' when you turn all these on... but you're not tricking physics. If you use an RGB 'white' source to illuminate a surface that is not R, G or B (example - Purple) it will look rather 'black'. This is because pigments reflect light.. purple pigments reflect purple light. If there is no purple in the source, then there's no purple to reflect.
  • 02.22.2016
  • Primary colors
  • Not sure of the point of this article??? Unless it's just to stimulate some conversation. The RGB thing is not new. Been around for decades (ala color television as mentioned). I'm heavily involved in LED usage. I've learned quite a bit over the last several years about it. Some interesting points: - RGB 'color blending' was patented by Color Kinetics. Even though it's 'obvious to one skilled in the art', the patent was issued anyhow. There was a 15 year battle to get the patent overturned (only partially successful). Phillips bought Color Kinetics, and thus obtained the patent. If your product is using RGB blending, you would be wise to contact Phillips before proceeding. - If you can actually "see" the three different primary colors, it's because the creator isn't PWM'ing them fast enough. If you rapidly move your eyes left/right, you'll probably be able to see the primary colors even clearer. - The possible colors that can be recreated in an RGB scheme are defined by plotting the 3 points in the 1931 CIE Color space --- Any colors inside the triangle can be recreated--- Anything outside of it can not. Google "cie 1931 rgb color space". - It's extremely difficult to nail yellow in production. This is because yellow is a very very thin slice of the color space. A small amount of drift will turn your yellow into green or orange. Unless you have a technician on the line tweaking each unit, or you sort LED's, you'll never keep it consistent in production. (Not to mention how much the wavelength drifts with temperature - which is why you don't see yellow LED tail lights on cars, but brake lights are almost all red LED's now). Couple nanometers, and you're not yellow anymore. DOT doesn't allow that. One of the major TV manufacturers started shipping RGBY televisions recently, almost certainly as a solution to this problem.
  • 01.29.2016
  • It’s always a capacitor
  • ****** But you would think that a service call on a 16-year-old AC system would at least offer to replace all the capacitors. ***** That's unrealistic. You're an EE, so you understand there is a limited lifetime to caps. It's probably fair to say that 98% of people surveyed have no idea what a 'capacitor' is or how to tell if it's gone bad. You think the AC service guys should be recommending replacing a part that hasn't failed, but doesn't necessarily have any sort of visible or measurable indication that it's going to fail?? (unless it's visibly bulging or leaking -- but they don't ALL do that). How are they gonna sell that idea to the 98% of customers? Nearly everybody will think they're trying to pad the bill. Some AC service guys may even have been slick enough to realize recommending replacement would be in the customers best interest ... But after a few dozen people telling 'em to pound salt, eventually they'll just stop asking. Way less "impedance" (repurposing an EE term!) to just come back next year and charge another $100 service fee when the cap dies...