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  1. hevans1944

    Need Help with auto switching Reverse Polarity Circuit

    @gunlocators might want to more thoroughly investigate "colloidal silver" by electrolysis. This process mainly makes ionic silver, NOT colloidal silver. Ionic silver is reduced virtually instantaneoulsy to silver chloride by chloride ions, particularly from stomach digestive acid or HCl...
  2. hevans1944

    Adding a timer to a stereo amp

    I would venture to guess that the original "speaker" in the timer is a high-impedance piezoelectric transducer. If so, there probably isn't enough power or signal amplitude to drive the 100 Ω resistor I originally suggested connecting across your two wires connecting to the amplifier. In other...
  3. hevans1944

    How to use a fs1000a transceiver set

    I would have thought so, but these devices were probably part of an OEM (Original Equipment Manufacturer) system designed for who-knows-what specification. I think if I had a pair, I would try to use the DATA input on the transmitter to see if a response resulted from the receiver. Guessing here...
  4. hevans1944

    How to use a fs1000a transceiver set

    I found this website which describes how to interface to a pair of Arduino microcomputers. Not sure why these FS1000a wireless transmitter/receiver pairs appear to be so complicated.
  5. hevans1944

    Adding a timer to a stereo amp

    Welcome to Electronics Point forums. Really? Making a count down timer, or trying to use "a battery kitchen timer" as a count down timer? Wow! What is RCA wire? Does the stereo AMP have stereo speakers connected to it? Would that be the LEFT stereo channel or the RIGHT stereo channel of that...
  6. hevans1944

    Replacement Power Supply Project

    No, you need about 22 VA: 11.13 VA from each half of the center-tapped winding. Most of this will be needed to provide continuous power to the main amplifier. The 48 V DC "phantom power" for condenser mics requires virtually no power.
  7. hevans1944

    Replacement Power Supply Project

    As @KMoffett said, the replacement transformer you selected is likely too small. You are confusing power (or VA) with current. The original transformer delivered 36 V AC at a maximum current of 0.62 A from a center-tapped secondary winding. This represents a maximum power (or volt-ampere)...
  8. hevans1944

    Big storm passed over head today

    My father was stationed in the South Pacific during the Korean War, somewhere near Australia I think. He used to say he wanted to go back and visit Australia, but that dream died with him. Anyway, everywhere he went he took hundreds of 35mm Kodachrome positive slides with his Argus C3 camera...
  9. hevans1944

    AC adapters

    Since you made this mod, wiring two 48 V batteries in series, I think it would be simple to connect a 48 V to 6 V DC-to-DC converter to just ONE of these two batteries. Such converters are readily available. You could even get REAL FANCY and arrange a MOSFET switched circuit to alternate the...
  10. hevans1944

    Newbie with a power supply question

    About the middle of the previous century our teacher was conducting a Science class on electricity and magnetism. Very elementary stuff. She asked each of us to go home and construct a project that used one or more dry cell batteries and then bring our project back to show in class. The usual...
  11. hevans1944

    LED lighting without power source

    I am going to stick with the Holiday Season Poltergeist (HSP) explanation. That's a nice picture with everything lit up properly, and the power utility getting its due.
  12. hevans1944

    Oscilloscope LINE trigger mode used for what

    Well, it didn't make much sense to me either (and still doesn't). The NTSC signal specifies vertical and horizontal sync pulses, so a properly designed TV will sync to the received signal, not to the local power-line frequency. I think the reasoning way back then was that using the power line...
  13. hevans1944

    Oscilloscope LINE trigger mode used for what

    Color TV horizontal and vertical sweep frequencies are synched to sub-multiples of the (approximately) 3.58 MHz chroma sub-carrier, whose spectrum is interleaved with the luminance spectrum to fit the additional color information in the same bandwidth as original monochrome bandwidth. This...
  14. hevans1944

    Oscilloscope LINE trigger mode used for what

    In really ancient times, before NTSC color TV standards existed, there was NTSC monochrome. This dictated a 60 Hz 2:1 interlaced field rate and a resulting 30 Hz frame rate. The horizontal sweep rate was 15,750 Hz, which resulted in a maximum of 15,750/30 = 525 horizontal lines. Not all of these...
  15. hevans1944

    AC adapters

    A buck converter is probably not what you need. A flyback converter and transformer with a rectifier on the secondary would be sufficient to run a 6V lamp load at 1 A.. I have attached a Linear Technology datasheet for their LT83000 series of Flyback Converters which are rated to operate with...
  16. hevans1944

    Oscilloscope ROLL mode used for?

    Back in the "good old days" we recorded slow-changing or infrequent events on strip-chart recorders because there was no such thing as a digital storage oscilloscope. These recorders varied in the number of channels recorded and the method of recording. Some used ink pens driven by servo-motors...
  17. hevans1944

    Oscilloscope ROLL mode used for?

    I don't think autistic idiot savants actually do any thinking. More likely they respond to whatever random meme presents itself for inspection. I think the psychobabble folks call this random or free association. Not sure what, if any, therapeutic value it has, but it seems harmless in Danny's...
  18. hevans1944

    New member and need help with electronics

    We need some background here. Are YOU your teacher's favourite student? If not, how much is she willing to pay for the talking moving picture box? How many "randomly selected sound" clips are stored in the box? This project sounds like a "smart phone" application to me. You get the "favourite...
  19. hevans1944

    Heatsinks for very hot Xbox Chips

    No, overclocking will increase the CPU power dissipation as well as its speed, but IF the CPU heat-sink, fan, and air circulation inside the box are poorly designed, the CPU can run hotter than desirable even at its originally specified clock speed. Most users do not attempt to overclock their...
  20. hevans1944

    Heatsinks for very hot Xbox Chips

    Gamers who are fond of overclocking their CPUs sometimes go to great extremes to remove heat: water-cooled heat exchangers and Peltier heat pumps are some of the "solutions" offered. Adding more fans, or a more powerful fan, is the least expensive solution, but in the end you are still left with...
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