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Produced by Burton Holmes Films during WWII, this black & white educational film is about Capacitance, the ability of a system to store an electric charge. It was made to educate U.S. Navy Radio Technicians and was probably standard viewing during training. Typical of government films made during the WWII timeframe, this film is outstanding in its use of both live action and animated sequences. Copyright is 1943.

Opening titles: United States Navy Training Film – Capacitance (:06-:32). Two uniformed men play pool. A narrator explains the flow of current. Animation shows a current flow. Resistor is explained. A pool table. Ball is hit by a pool cue. Pool balls on the table. I = E/R (:33-2:15). A resistor and a circuit are explained. Movement of electrons shown with animation between A and B. A is negative and B is positive (2:16-4:04). More energy being stored with larger plates is shown via animation. A man uses a capacitor. A hand unscrews a cap holding air in a tire. Air tank gauges. When valve is opened, air rushes out (4:05-6:01). A man connects a power supply and charges a condenser. Voltage is increased. Q is quantity of electricity stored. Plate spacing. The plate area (6:02-8:09). The dielectric is an insulating material or a very poor conductor of electric current. When dielectrics are placed in an electric field, practically no current flows in them because, unlike metals, they have no loosely bound, or free, electrons that may drift through the material. Glass is used as a dielectric. Two or more condensers are used (8:10-9:40). Voltage source increases. A man performs a test with wires and condensers. Large condenser equals a larger spark. A screwdriver captures the spark. Title: end of part one (9:41-10:55).

Title: Capacitance – Part two. A circuit with a battery and a condenser is shown. I = 6 volts divided by 1 ohm or I = 6 amps (10:56-11:57). I = 1.5 volts divided 1 ohm. Different current flowing opposing the battery voltage (11:58-13:24). Charge across the condenser builds up in a graph shown and explained. Farads, ohms explained. A graph shows a charge falling. T = RC, The RC time constant, also called tau, the time constant of an RC circuit, is equal to the product of the circuit resistance and the circuit capacitance. R – C Time Constant resistance machine (13:25-16:14). The machine is explained and gauges are shown. A man points out parts on the machine. An oscilloscope is a device for viewing oscillations, as of electrical voltage or current, by a display on the screen of a cathode ray tube (16:15-18:10). Oscilloscope’s screen, spot on the screen produces same curve as that on a graph. Man uses a marker on the screen (18:11-19:44). Close on the oscilloscope’s screen. One condenser is disconnected. Watch the meter. Resistance is cut in half. Resistance and capacity. Oscilloscope screen shows curve. Resistance regulates flow (19:45-21:55). Title: Capacity with Alternating Current. Condenser is reversed in animation. Alternating current is explained and shown via animation (21:56-23:21). The narrator amplifies his voice, he shows a microphone amplifier. Diagram of amplifier circuit at work. The narrator speaks to the viewer (23:22-25:28). End credits (25:29-25:38).

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  1. wbeaty on June 13, 2022 at 5:57 am

    It’s actually correct! Many of these training films get it wrong, showing nonsensical physics, and teaching misconceptions.
    It shows that… electricity flows *slowly* in circuits, electricity passes *through* capacitors, and electricity always flows in complete circles (where electricity cannot be a form of energy.) A "charged" capacitor contains the same amount of electrons as an "uncharged" capacitor, since capacitors store energy, not charge. They even show the random thermal vibration of electrons in metals! These guys must actually know some physics! That’s rare.

    Only one slight mistake, mostly present in Part 2… they constantly speak as if "current" was a substance, as if it could flow from place to place. No, the only flowing substance here is called "charge." If they deleted the word "current" and instead said "charge-flow" and "flow of charge," then their language would be far more correct and consistent.

    "Current" doesn’t flow in wires. Hydraulic analog: when describing pipes and hoses, we speak of flowing water, not "flowing current." There is no magical substance called "current" which flows in pipes, WATER flows in pipes. When we turn on a faucet, "current" doesn’t fill our bucket, instead it’s filled with WATER. The same is true with electricity. In electrical explanations, we’d correctly discuss charge, charge-flows, or perhaps Quantities of Electricity, and the flows of "electricity" called electric currents. Traditionally, in physics the word "electricity" means charge. (The flows of electricity are called currents, and an amount electricity is measured in coulombs, where electricity is not some sort of flow-rate!)

    The producer screws with the audience, where in part two, suddenly the Trusted Authoritative Voice is revealed to be an actual human being! BREAKING THE FOURTH WALL! I thought you weren’t supposed to do that, not before the invention of Television!

    Also, electron have holes in the center? No, electrons are little half-inch paper circles, those "adhesive reinforcements" for ring-binders. Any office had little boxes with thousands of those white circles. Apparently the size of their animation-frame isn’t tiny, not like a modern computer screen! Heh.

  2. sengoku kaiser on June 13, 2022 at 5:58 am

    Wow I learned more in 20 minutes of this video than I did in a year of my electronics apprenticeship

  3. mysock351C on June 13, 2022 at 6:00 am

    I like the SpagettiO’s for electrons. Now all we need is some quark marinara sauce and we’re in business.

  4. Luminous Fractal on June 13, 2022 at 6:02 am

    if only someone had told me volts is a pressure measurement it would all have been so much clearer. thank you

  5. jim hale on June 13, 2022 at 6:03 am

    Man, I miss these old films and the NAVPERS books… Thank you for posting this.

  6. Shane Johns on June 13, 2022 at 6:05 am

    I’d love to know where the US Navy requisitioned the tire from. 🙂

  7. Robert Troughton on June 13, 2022 at 6:05 am

    I want that oscilloscope

  8. Jonsey on June 13, 2022 at 6:05 am

    The fact that naval training material sometimes 80 years old are still referenced constantly and that you can teach yourself anything that happens on a vessel from no prior knowledge to workable familiarity using naval training books is the greatest compliment that I can imagine. An almost sacred ideology embraced by the Naval Technical Training Command from before WWII was adopted. The simple, straightforward approach to teaching people from a wide variety of backgrounds, many with no prior formal training, who must become functional as soon as possible are the realities of war and the Navy is simply the best at compiling these manuals.
    God Bless the Navy and the NTTC.

  9. LincolnTek on June 13, 2022 at 6:07 am

    Funny they used billiards to demonstrate these examples. I was taught the same way but the medium example was water. Electricity flows like water. For example, the resistance scenario using water, imagine water running through a hose, kink the hose and you have a point of resistance.

  10. Tom MacDonald on June 13, 2022 at 6:08 am

    Somehow (I haven’t figured out exactly) this film has got to be Racist.

  11. Йош Корала on June 13, 2022 at 6:09 am


  12. Something Someone on June 13, 2022 at 6:09 am

    I love these old films. I always learn more about subjects I thought I already understood fairly well

  13. Stu Reedy on June 13, 2022 at 6:09 am

    Don’t let out the magic smoke!

  14. Vince Mayo on June 13, 2022 at 6:12 am


  15. Bill Kitchen on June 13, 2022 at 6:13 am

    I wish I’d seen these films when studying for the radio amateur’s exam. They explain it very well.

  16. Mark Honea on June 13, 2022 at 6:14 am

    Digital multi meters are great, but they can not show the analog properties of many components, like the old Simpson V.O.M. .👍

  17. Ready Teddy on June 13, 2022 at 6:15 am

    Film does not not make it clear why decreasing the distance between the 2 plates increases the capacitance and conversely increasing the distance decreases the capacity. Same thing regarding the dielectric material. Why does denser material increase capacity?

  18. Philippe Senechal on June 13, 2022 at 6:16 am

    25.4k Ohms=(-)v(÷)i

  19. RayDT on June 13, 2022 at 6:17 am

    0:55 Superconductivity had already been demonstrated by this point in time, so this statement isn’t exactly true.

  20. NIC FEL on June 13, 2022 at 6:17 am


  21. Charlie Ramirez Animatión Studiös on June 13, 2022 at 6:21 am

    17:18 We are in 2021 and oscilloscopes are still very expensive, even to study electrical engineering they are almost relics that they do not even want to touch …. How much would have cost in the 30-40’s that single channel oscilloscope?

  22. M Wing on June 13, 2022 at 6:22 am

    A wax capacitor !! LOL ;O) Also a good visual for ground potential.

  23. Magneticus Attractus on June 13, 2022 at 6:24 am

    Where was this video 10 years ago when I had the FCC hounding my heels.

  24. Nigel Clark on June 13, 2022 at 6:24 am

    Very good lecture and
    excellent coverage on
    capacitors , the good old days .

  25. Prakhar Mishra on June 13, 2022 at 6:26 am

    9:56 did he really hold 800v carrying wires in both of his hands?

  26. m3sca1 on June 13, 2022 at 6:28 am

    pulled along by tension…not pushed along by pressure

  27. The Swartz on June 13, 2022 at 6:29 am

    That’s why they’re called "Condenser Mics"…. ahhhh…. I always wondered why.

  28. Teresa Watson on June 13, 2022 at 6:30 am

    Now let’s see the thevenin equivalent pool table compared with the norton equivalent pool table. LOL

  29. Disleelandia on June 13, 2022 at 6:30 am

    I hope more training was given before sending a soldier into battle to apply this info! LOL

  30. Tariq Hakeem Sangi on June 13, 2022 at 6:36 am

    Very informative video 📸

  31. NotMarkKnopfler on June 13, 2022 at 6:38 am

    Legend says if you open up a battery it’s full of billiard balls…

  32. What The Function on June 13, 2022 at 6:38 am

    Please don’t use a permanent magnet on your oscilloscope screen kids

  33. d e austin on June 13, 2022 at 6:38 am

    well, I was army, but I gotta admit those navy types are pretty intelerg -entirll – pretty smart.

  34. TechnoWizard on June 13, 2022 at 6:39 am

    6:01 There it is the accursed M for micro farads, but in SI units they should use the greek letter mu, “μ" for micro, instead of M for mega! This maddening atrocity goes back to 1943 at least? Utterly frustrating…

  35. y z on June 13, 2022 at 6:39 am

    This film is more better than the modern course, easier to understand.

  36. William Chaves on June 13, 2022 at 6:40 am

    The answer is a commercial!

  37. Philippe Senechal on June 13, 2022 at 6:41 am

    25.4k Ohms=(-)v(÷)i

  38. GP4 Themes on June 13, 2022 at 6:43 am


  39. lionel shaneyfelt on June 13, 2022 at 6:44 am

    Youtube algo supplying thine gems.

  40. TVP-RBE-better world, STEM on June 13, 2022 at 6:44 am

    Please look up to "the Venus project" it offers solution to most of the problems we face today.War, poverty, hunger, starvation, illnesses, crime, deprivation, human suffering can be solved with THE VENUS PROJECT. It offers method to achieve better world. The Venus Project is not perfect/Utopian, its just much better than what we got today.

  41. WRENCH g on June 13, 2022 at 6:45 am

    You got that right. It’s also why all of these training videos are still used to this very day. Many Union and trade schools use them. Well like they say, if it ain’t broke, don’t fix it.

  42. ImarSchmo on June 13, 2022 at 6:46 am

    @19:45 "This mark represents the time constant …" Which should be at, roughly speaking, somewhere north of 1/3 full scale (37%), but it’s not. The scope trace is not moving downward either. This is because the actual demonstration, as far as the scope is concerned, is showing two RC time constants, i.e. the demo board and the input coupling high pass filter characteristic of the AC coupled scope. The scope should have been DC coupled, which may have been impossible as many scopes of that era where only AC coupled. Notice how, at higher frequencies later in the demo, the scope trace goes right through the marker line. That’s a sure indication that the scope is AC coupled.

    @24:12 "This is a diagram …" I have to call it an awful diagram! It shows the first amplifier’s plate attached to battery positive and the second amplifier’s grid attached to a negative. Although the plate should be positive and the grid should be negative, diagrammatically connecting them to batteries is crazy. Yes, you ‘could’ make this work by having an impedance on ‘the other end’ of the battery, but for some very good reasons it’s not practical. Schematically, more correctly diagrammatically, a battery represents a voltage node, meaning there is no changing voltage. And they’re trying to demonstrate changing voltage is coupled through a capacitor. ??? This oversimplification, if that’s what it’s supposed to be, bothers me greatly because this training film is teaching something that must later be unlearned. Perhaps the film’s author thought his audience was too dumb to notice, so it didn’t matter. 🙁

    I don’t think a competent engineer ever reviewed this film. We actually won that war. How?

  43. Tri Pham on June 13, 2022 at 6:46 am

    Gold is best conductor

  44. Jay Greider on June 13, 2022 at 6:47 am

    I was a radioman/crytographer in the Navy during Vietnam. I never opened a unit. That was left to the ET’s.

  45. Haniel Nunes on June 13, 2022 at 6:48 am

    Thank You so mutch for share!!

  46. Anthony lopez on June 13, 2022 at 6:49 am

    I wonder if this fellow is still alive, so many years has past since this video.

  47. LesB SoCal on June 13, 2022 at 6:51 am


  48. jamie smither on June 13, 2022 at 6:52 am

    I now understand how the 555 timer works!

  49. Level Three on June 13, 2022 at 6:52 am

    23:46 , this dude looks nothing like I imagined.

  50. crush537 on June 13, 2022 at 6:56 am

    Information was delivered much cleaner before all the experts screwed everything up. Go Navy!

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