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Video signal amplifier.

Discussion in 'Audio' started by HANKMARS, Jul 28, 2019.

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  1. WHONOES

    WHONOES

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  2. hevans1944

    hevans1944 Hop - AC8NS

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    Tom had a huge vested interest in DC dynamos, which is why he vigorously opposed AC power distribution. Tesla and Westinghouse owned the patents to polyphase AC power distribution, and given the shabby way Edison had earlier treated Tesla, Tom was not likely to have obtained licenses to use them on favorable terms. Electrocution was not an issue, it was a Red Herring that Edison tossed out to scare the public. It is likely that Edison did not understand polyphase AC power distrubution, nor possess the math skills necessary to understand it. I am sure he employed plenty of degreed engineers who did understand it, but it would not have been in their best interests to try to force Edison to accept it since Edison had so much invested in the construction of DC power plants to power his patented incandescent light bulbs and various (public domain) DC traction and fractional horsepower motors.

    Tesla's invention of the AC induction motor, and the later development of small AC/DC "universal wound" motors, pretty much sealed the fate of the Edison DC power distribution system. Edison might have survived a little while longer using DC power distribution by building high-voltage motor-generator sets to more efficiently transmit power over longer distances, but it would have been impossible in the long term to compete with AC transformers.
     
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  3. HANKMARS

    HANKMARS

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    That was the hearsay I considered, was the demonstration of electrocution of a goat or some such creature, that went airy. Ultimately, I consider that transmission of DC power would have been the killer of a DC system.
     
  4. HANKMARS

    HANKMARS

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    One aspect of calculating the potential energy of my defined mass, 2000 Kgm, is that it would give me an indication of energy required to lift the mass the stated 3 meters. If I used friction-less, ideal machinery to raise the ton, the energy used would equal the potential energy of the mass, once secured and sitting at rest. Agreed, or have I overlooked a factor and made a grievous error? Let's make a visual demonstration of the expenditure of the potential energy of my one ton (metric) mass, once it is released and driven into motion by gravity. Again, I will be using ideal mechanical apparatus which will resist the inertia of the mass and employ an electronic brake, if you will. The mechanical action of the resisting device will be so designed as to create an electric current in traditional manner. This will be sent to an appropriate heavy load which should introduce reverse EMF to the generator, creating a braking effect. Expending my potential E of 0.016 KWHr in the form of powering a 100 watt light bulb (perfect style, no efficiency coefficient needed), I could energize my bulb for 0.16 hour. 60 minutes × 0.16 = 9.6 minutes. Just using dead reckoning, I am inclined to disbelieve these findings.
     
  5. hevans1944

    hevans1944 Hop - AC8NS

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    Dead reckoning? That's a navigation procedure I haven't seen used since GPS became widely available worldwide. My father used to use dead reckoning to plot the course of the B-47 bomber he was responsible for navigating from his base in the United States of America (USA) to some target for his nuclear weapon in the Evil Empire of the Union of Soviet Socialist Republics (USSR) during the 1950s. Why use dead reckoning when he had a sextant, an ephemeris, and radar navigational aids? Stealth. At the cruising altitude of the B-47, if there was no visible contrail, and no glint from sunlight, the airplane was virtually invisible, even if you knew where to look for it. Back then, there was no effective way to "shoot it down" unless you already had fighter aircraft pre-positioned and waiting. So leave the radar emitters off until the bombing run to lessen the chance of an unpleasant surprise.

    The Strategic Air Command (SAC) B-47 mission was considered to be a one-way trip, with no practical return-to-base, because it was assumed that after we started slinging nukes at each other there wouldn't be any bases left to which they could return. Nor any aerial refueling tankers to get them there. So, yeah, take "fixes" with your sextant on the Sun, the Moon, and/or bright Stars to plot where your airplane was, then use dead reckoning to predict where it would be when you took the next sighting with your sextant.

    Salt-water sailors have been using dead reckoning since at least the time of Columbus, attempting to predict where they were going based on some uncertain knowledge of where they had been, how long and how fast their ship was "making way" and in what direction that was, despite the vagueries of wind, currents, tides, and weather. It is indeed fortunate that they sailed on a globe for otherwise their ships would surely have fallen off the Earth.

    Soooo... what was your "dead reckoning" that led you to disbelieve your results? About 9.6 minutes is quite accurate BTW, considering you know nothing about the efficiency of converting graviational potential energy into electrical energy. That's also about how long it would take a motor, consuming electrical energy at a 100 watt rate, to raise a 2000 kg mass a vertical distance of 3 m in the Earth's gravitational field. All that aside, pumping water from a low place to a higher place to fill an hydroelectric dam is still the most efficient way to store electrical energy for later on-demand use, said pumping energy being typically derived from a solar array or a wind farm or similar "renewable," but not continuous, source of energy. Raising and lowering non-liquid weights to store large amounts of energy is just not very practical.
     
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  6. hevans1944

    hevans1944 Hop - AC8NS

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    Edison's electrocution of animals, including an elephant, was quite well documented on motion picture film. No hearsay involved.

    Today, the transmission of DC power at megavolt potentials is a "done deal," both in the USA and abroad, because of the availability of solid-state switching devices that operate as synchronous rectifiers on the transmission end and as DC-to-AC inverters on the receiving end. DC power transmission, among other advantages, avoids the reactance issues that plague AC power distribution and require expensive power-factor correction to avoid excessive losses. See, for example, the Pacific Intertie that brings inexpensive electricity south to Los Angeles from its hydroelectric generating source on the Columbia River in the Northwest using high-voltage DC transmission lines. Well, the power companies hedged their bets by building a conventional AC high-voltage intertie too, that was strung slightly west of the DC intertie, but the DC intertie has proven to be very successful. Never hurts to have a little redundancy in large systems such as interties.

    Neither Edison nor Tesla had the benefit of this technology of course, and it is totally impractical, at least today, for distribution of electrical energy to homes and businesses. But technology is increasing at an exponential rate. Who knows what is impractical today that will be commonplace in the future? I didn't foresee that "Power Over Ethernet" or PoE would today include infrared optical laser power transmitted over plastic fiber optics to provide both Ethernet communications but also power to electronics at point-of-use, after conversion back to electrical energy with photo-voltaic cells. This proves handy when stringing Ethernet connectivity to remote service areas, even if regular utility power happens to be available at the destination.

    So how goes the roll and un-roll 'em up lipstick camera project?
     
    Last edited: Aug 19, 2019
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  7. HANKMARS

    HANKMARS

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    Camera project still remaining warm on back burner. I got a few licks in on another pet project this last week and acquired a "money" project that should wrap up by end of next week. In this instance, money project does not refer to a motherload strike but rather a project that offers a few alms for my time spent and work completed.
     
  8. HANKMARS

    HANKMARS

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    Dead reckoning or calculated results based on guesswork, or in this case, intuition. I was unaware that pumping stations were used in such massive hydroelectric operations as dammed water ways. My "volume" of stored energy is more so in the neighborhood of that required to power a single family dwelling. I believe it to be quite possible to extract the potential energy of a solid mass with an efficiency of no less than 80 percent. Same goes for the storing end of the process. That 80 percent figure is based on the power applied to the mechanism which will raise the mass and negates the conversions of wind, solar, or animal power converted to electrical power. Fabricating water tight vessels and gaining the height to result in usable pressures, plus the volume of water needed, would seem to eliminate a water/turbine system from these small energy situations. I do like the idea of thermal storage systems using water even though large volumes of water are needed. Speaking of efficiency of energy conversion, I will stick to my guns on the concept of potential energy equals energy required to reach a same level of energy stored. Therefore if I wish to raise a solid mass to a point where it will have a potential energy of 0.02 KwH, I would guess that my motor slip and line losses and friction losses will give my an efficiency coefficient of 30. Therefore, 0.02 / 0.30 = .066. Therefore, raising my mass to 3 meters with a rate of 100 watts would take more like in the neighborhood of 30 minutes.
     
  9. WHONOES

    WHONOES

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    Look at the link below. It details a hydro storage system in North Wales. Water is pumped from the lower lake to the upper lake at night when demand is low and power stations are still generating. The facility is then used to generate power during daytime peaks.

    https://en.wikipedia.org/wiki/Dinorwig_Power_Station
     
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  10. HANKMARS

    HANKMARS

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    I look forward to seeing the link you have posted but am interested in finding a few facts about a particular formula. I had asked this question on the "stack" but was told to go do my homework. Sort of a pat answer by those who have not done their homework yet hold the degree as if they had. Anyway WHONOES, I am not coming at you as being a physicist, but rather hoping someone in the know may stumble upon this text and supply a valid answer. In the formula for potential energy; mgh or mass (in kilograms) × gravity (9.8 meters per sec/per sec × height (in meters), I believe that the gravity factor needs to be calculated. The examples I have seen use the value 9.8 for this factor. As I understand this formula, it is used to calculated instantaneous velocity. After one second of free fall in Earth's gravity, an object's instantaneous velocity will be 9.8 meters per second. At the two second mark of free fall, the object's instantaneous velocity will be 19.6 meters per second. At three seconds, 29.4 meters per second, and so on. I am thinking that the calculated value using the gravitational formula is what should be used in the potential energy formula. I will be cracking open some old physics books and try to find these answers as the high brow minds seem a little busy calculating black hole mass and other improvable answers. Just sayin. I'm a little pressed for time and out of data at home but will get to your posted link soon. Thank you.
     
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  11. HANKMARS

    HANKMARS

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    I find lead/acid batteries to be expensive, dangerous, heavy, high maintenance, and to have a relatively short life span but also, they seem to be the most popular storage system for residential alternate energy. Remember, I may very well find myself deep in the Congo, at night, in complete darkness, just wishing I had a couple 10 watt LED bulbs that I could light until dawn. Is it really practical to pack heavy, expensive lead/acid batteries to my little grass shack? A helicopter would be handy but I don't have one. It would probably just be me and a couple three other asses dragging equipment through the jungle. Now a 300 gallon caged poly tote tank is light weight. A hardy lead screw and some roller ball bushings, a few lengths of pipe, a couple gear heads and a frame work for a heavy flywheel, and a few hundred gallons of water, and I think I might be able to light up my little grass shack over night. Unincorporated villas in distant, difficult to reach destinations, will be the working places for these archaic designs that I have in mind.
     
  12. WHONOES

    WHONOES

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    If you only want to power some LED lamps in the middle of nowhere, have you considered using a Sterling cycle engine to drive your generator. Being and "external combustion" motor, you could burn absolutely anything such as scavenged wood or dead physicists to power it.
     
  13. hevans1944

    hevans1944 Hop - AC8NS

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    @WHONOES: Don't forget it also has to operate a video amplifier driving five hundred feet or so of whatever wind-up cable, and presumably also power-up a lipstick camera at one end of the cable and perhaps an LCD monitor at the other end. The excursion to the African Congo seems to be a new requirement, totally unrelated to the side topic first mentioned in post #72, of how to store electrical energy kinetically using either flywheel or water-powered generators. On that somewhat off-topic subject, first begun in post #59 with the question "Does this seem correct?" it does appear that @HANKMARS has zero "hands on" experience generating electrical power by any means, much less storing the electrical energy, which is a totally different and much more complicated subject. This is so typical of almost everyone: they have not a clue how much effort is required to "light up" their dwelling, whether it be a penthouse overlooking "The Strip" in Las Vegas or a grass hut in deepest, darkest, Africa on a cloudy overcast, moonless, night.

    I had my first "hands on" or, rather, "feets and legs on" experience, when I installed a bicycle DC generator to power up a front headlight as well as a rear red tail-light. The generator was physically small, maybe two inches diameter and four inches in length, and was spring-loaded against the side of a tire to spin a small ribbed shaft protruding from one tapered end. See image below.
    [​IMG]
    I used my bike to deliver newspapers after school in a rural area around Phoenixville, Pennsylvania. It was a long route and a lot of newspapers, so sometimes it was dark before I finished. I thought a front headlight would help me find my way in the dark. Well, maybe it would if it were fifty watts or more rated filament power, but the generator is only rated 12 V at 6 W. And of course the light intensity varied with the bicycle speed. I later (much later) learned that bicycle-mounted lights are there to make the bicycle and its rider more visible to oncoming vehicular traffic. They are not intended to effectively illuminate the road. Today you will see many bikes on the road with LED-equipped white-light headlights and red tail-lights, battery powered instead of generator powered because convenience trumps cost and a battery provides constant illumination at any bicycle speed.

    Later in my (then) young life, I found out how much power a human being could sustainably generate for brief periods of time. The number is between fifty and one hundred watts, depending on physical condition and motive, for perhaps as long as one hour but more likely for ten or fifteen minutes. The most efficient energy conversion seems to occur when pedaling a recumbent bicycle driving the generator. A stand-up posture is too quickly tiring, and using arm power from a sitting position is not very effective either, although both are effective strength-building exercises. A rowing machine which exercises both arms and legs may be even more efficient, but I have never seen one used to generate electrical power. Perhaps the mechanical complexity obviates their efficient use for that purpose. Are there any genius mechanical engineers out there who can definitively answer this question?
     
  14. Abderian

    Abderian

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    If you don't match the impedance of your cables at both ends there will be a huge mess of your signal.
     
  15. duke37

    duke37

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    You only need to match cables at the load end to stop reflections, then the cable looks like a resistor at the source

    Potential energy is mgh where g is 9.81 unless you are on the moon. I think you will need a lot of water high up in the forest canopy to store sufficient energy.
    Power will be energy used per second.
     
  16. WHONOES

    WHONOES

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    No. you need to match cables at both ends.
     
  17. hevans1944

    hevans1944 Hop - AC8NS

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    This thread has wandered way off the original topic, which involved attempting to transmit composite (presumably NTSC or PAL) video a long distance, five hundred feet, using ordinary shielded four-conductor instrumentation cable wound up on a six-inch diameter reel, said signal to be boosted by an LM747 op-amp. Somehow a requirement to do all this at night, deep within the Congo jungle, using only simple energy storage schemes came up in @HANKMARS post #71. For seasoning, a discussion of gravitational potential energy for use as a possible energy storage mechanism, worthy of a thread in its own right, also crept into.

    So, it seems to me that this thread, having now wandered off to Africa, is going nowhere toward solving the original problem presented in post #1 and should be closed. Perhaps @HANKMARS could start a new thread with some specific, realistic, requirements of what he wants to DO instead of posting ill-advised notions of how to do it. It is our job to respond with notions, ill-advised or not, depending on what information is provided. Most of us here know his original approach will not work because of several design deficiencies. We also know that all of our suggestions for designs that could work have been ignored. What is the point of any more posts to this thread?
     
  18. WHONOES

    WHONOES

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    Perhaps the originator could enlighten us but hen...………………………………………….maybe not.
     
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  19. duke37

    duke37

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    Why is this? If the cable is matched at the load end, there will be no reflections to be absorbed and the cable will appear as a resistance equal to its impedance. A resistance at the source will just waste power.
     
  20. WHONOES

    WHONOES

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    May 20, 2017
    HANKMARS likes this.
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