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  1. Janus

    Beauty of old electrical and measuring things, etc.

    My daughter took a photography class in High School (she graduated in "06), and they used film and wet chemistry. From that, she went on to be a photographer for the school paper.
  2. Janus

    Beauty of old electrical and measuring things, etc.

    Pretty much what happened for me. I moved to an apartment which had no place to set up a darkroom. The equipment just sat around taking up room and collecting dust until I sold it.
  3. Janus

    Beauty of old electrical and measuring things, etc.

    My "first" camera was something similar to this: Not exact, it was a Kodak, and a fold-out, but some of the details were different. Again, it was my parents. I started using it when I wanted to get into having my own dark room set up. It was perfect for starting out, as the negatives were...
  4. Janus

    Beauty of old electrical and measuring things, etc.

    We had the projector too, though I don't know what came of it. Did anyone else's folks have the Light Bar for the camera? It Looked like this: https://d3h6k4kfl8m9p0.cloudfront.net/stories/IhHqBoi5vwc61d7GHxm6Hw.jpeg It was used for indoor filming. The camera would mount on top.
  5. Janus

    Beauty of old electrical and measuring things, etc.

    In the same vein, here's my "used to be my parents" Bell and Howell movie camera and case, from the 1950's
  6. Janus

    Beauty of old electrical and measuring things, etc.

    @dlgoff 's post reminded me of some pictures I took in an antique shop a while back. They had some old equipment that had been converted into lamps:
  7. Janus

    Why will 240 volt condenser kill me but not 7,000 volt electric fence?

    Voltage doesn't kill, its the amperage passing through your body that does. The 230 volt condenser had enough stored energy to be able to deliver enough amperage to kill you under the right conditions. ( luckily for you they were not.) However electric fences are specifically designed with...
  8. Janus

    How do power sources work?

    If it is a regulated voltage source, the amp rating tell you how many amps a load can draw without it effecting the output voltage. So for example, with a 5V 2A source, you could connect up to a 2.5 ohm load and the source would be able to maintain the output voltage ( though in reality, you...
  9. Janus

    Beauty of old electrical and measuring things, etc.

    I remember when tube testers could be found all over the place, even in grocery stores.
  10. Janus

    How does a hairdryer produce 1500 watts?

    Challenge accepted! 1 coil using outputting 1 Watt, total resistance 1 Ohm Two coils, each outputting 1 watt, total output 2 Watts, total resistance 0.5 Ohms Three coils outputting 1 Watt each. Total output 3 Watts. Total resistance 0.333... Ohms
  11. Janus

    How does a hairdryer produce 1500 watts?

    If you assume an ideal voltage source, then if you plot amperage (red line) and Power (blue line) against increasing resistance, then you get something like this: With both amperage and power tending towards infinite as R decreases and tending to zero as R increases (resistance increases from...
  12. Janus

    How does a hairdryer produce 1500 watts?

    That would be true if you had a constant current source, rather than a constant voltage one. With a constant voltage source, current varies according to the load by I=V/R. Power is I x V, so it can also be expressed as P = V2/R Lower resistance lead to more power used by the load. If you had a...
  13. Janus

    How does a hairdryer produce 1500 watts?

    When the resistance of your resistor matches the impedance of the supply. Imagine your power source as a perfect battery with a resistor in series with it. This resistor represents the impedance of your source. When you attach a load to this, the load is in series with the impedance. For...
  14. Janus

    Beauty of old electrical and measuring things, etc.

    The basic system has been explained. For the pilot, It is used this way: you tune your VOR receiver to the station you are using to navigate by. Then you adjust your VOR to the heading you want with respect to the station. A indicator will tell you whether you are flying to or away from the...
  15. Janus

    Beauty of old electrical and measuring things, etc.

    I used to have a camera like the one on the left. It had been my parent's. I even used it when I was first into photography back in the late '70s. The negatives were large enough that you could produce a good print just using the contact method, and without needing a enlarger. I do still have my...
  16. Janus

    Phone charger bath accident

    Here's something I've seen quite often: three prong outlets installed "upside down". It may not seem like that great a deal, but the ground plug should be at the bottom. The reason for this is that if the plug is somehow wiggled so that it starts to the come out of the outlet, you want the...
  17. Janus

    Can I use a relay to wire DC lights to a speaker?

    Q1 is a transistor. It can act somewhat like a current controlled switch, but also as an amplifier where a small signal can be used to generate a stronger version of the signal. This is what it is be used for here. The "output" of the transistor is applied to pin 5 of the LM3914 IC, which can...
  18. Janus

    Dollar Store Pumpkin Light Solar Conversion

    Your amperage is incorrect. The amperage will still be .3A. Think of it this way, if you were to just hook two lights in series to a 2.5V source, you would be doubling the resistance and thus halving the current. 5 in series will increase the resistance by 5, but you are also increasing the...
  19. Janus

    How does fm actually suppress noise

    Put simply: AM, being amplitude modulation, is dependent on the strength of the signal. It is the variation of the signal amplitude that carries the information. If there is noise at the frequency of the transmission, Say a spike from some outside source, the receiver treats it just like a...
  20. Janus

    I don't understand how gates work.

    Yes, it the presence of voltage. Typically, a voltage below a certain level is considered a "0"(low) and one above a certain level is a "1"(high), with a "undefined" region between the two.
  21. Janus

    Need a circuit: 2 lights, 2 switches

    Do you need the switches to be able to both turn on and off the lights, or just turn them on? (IOW, do you need to be able to turn off L1 from either S1 or S2 no matter which one you used to turn it on?) If you just need to able to turn them on : I'd use 1 SPST switch (S1) wired in parallel...
  22. Janus

    Radio waves travel at speed of light?

    Let's see, the speed of light is just about 300,000 km/sec, so it should take 1/300,000 = 3.33 microseconds to travel 1 km. This is short but still an easily measurable time period. I've never heard of radio waves taking seconds or milliseconds to travel a kilometer or two.
  23. Janus

    Did i do this k-map right?

    you looped `A`BCD and A`BCD, so how did you end up with A`BCD?
  24. Janus

    Did i do this k-map right?

    There is a problem with the third term of your answer.
  25. Janus

    Tv rating

    They have a couple of ways. 1. Nielson families. Certain families are chosen by demographic and given a device that tracks their viewing habits (In the old days they had to keep a viewing journal. ) Each family respresents a certain percentage of the viewing public. 2. Telephone...
  26. Janus

    Resistors, How to decode the resistance fom the color bands.

    Again, why do people need a mnemonic to remember the order of the spectrum? Just visualize the colors and it's obvious what order they should go in. To me, its more difficult to remember the the mnemonic. (I'd probably have to visualize the spectrum and recreate it from that, and what would...
  27. Janus

    Resistors, How to decode the resistance fom the color bands.

    You know, I could never figure how those mnemonic sentences are susposed to be easier to remember than just remembering the order in the first place. What is so hard about remembering , Black, Brown, six colors of the spectrum in order, Grey, White? I mean, the order of the middle six...
  28. Janus

    Light Up 7 segment display

    Your common cathodes (pins 3 & 14) should go to gnd.
  29. Janus

    Three questions: Motors, Generators, Batteries

    First you have to understand why Iron is attracted to a magnet. The atom that make up Iron form magnetic domains (essentially microscopic magnets). In their normal state they are all pointing in random directions and thus cancel each other out. When you place Iron near a magnet, the lines...
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