Search results

Search Forums New Posts
  1. hevans1944

    Led Lamp

    You should at least wire an in-line glass cartridge fuse, about 1 A SLO-BLO, in series with one of the red wires before connecting it to a power cord, Maybe wire an in-line switch in series too so you can turn it on and off. You can purchase in-line fuse holders online, as well as in-line rocker...
  2. hevans1944

    Counter Circuit Troubleshooting

    Well, a schematic instead of a wiring diagram would be helpful... I don't feel too inspired to look up pin-outs for your counters, decoders, timer, and whatever. If the schematic accurately reflects what you have actually wired together, perhaps we can figure out how to make it work properly.
  3. hevans1944

    Led Lamp

    A description here for the power supply alone says the red wires connect to AC power and the black and white wires connect to the LED. Scroll to the bottom of the web page to see "datasheet". Don't you just love all the undocumented Chinese "stuff" that is spewing forth to land around the...
  4. hevans1944

    Help with time counter for wildlife research

    Here is a $51 timer that is powered with a lithium-ion battery, said to be good for ten years. A simple contact closure starts or stops the timer. Readout on LCD display in hours and minutes. See attached PDF for full specifications. Or perhaps you could hack a cheap kitchen timer to add an...
  5. hevans1944

    DIY high precision linear pot. Cheap too if possible!

    So, it sounds like you are investigating a small population's ability to "track" a moving target using a slider. Perhaps a "bouncing ball" target on a video monitor? That could be an interesting experiment to measure the "frequency and phase response" of a human being in a closed-loop...
  6. hevans1944

    Capacitor confusion

    Capacitors are the electrostatic complement to electromagnetic inductors. Both capacitors and inductors store electrical energy, usually for only short periods of time because there are electrical losses associated with both devices. Capacitors store energy in the electrical field between two...
  7. hevans1944

    Wattmeter with analog output

    Well, I try to be helpful, but the OP usually doesn't provide enough information for a definitive answer.
  8. hevans1944

    What does the symbol mean?

    The symbol on the 33250A means the shield of the BNC is not connected to Earth ground, but will tolerate up to 42 V peak voltage between the shield and Earth ground. The symbol on the 6614C means the power supply outputs are not connected to Earth ground, but can be "floated" ±240 VDC with...
  9. hevans1944

    Wattmeter with analog output

    I'm confused. An internal combustion engine (ICE) produces shaft horsepower that could be used to turn the shaft of an AC alternator or DC generator providing electrical current to a load. Where does "power drawn by an AC motor" enter into this picture? Is this a single-phase or poly-phase AC...
  10. hevans1944

    NP61 Projector

    Here appears to be a projector lamp housing with lamp installed for $115.00. It will be difficult to build an LED illumination system that is less costly.
  11. hevans1944

    Before The Electronic Projects

    Nice job. You might want to glue some short-pile "outdoor" carpet to the top so as to trap small parts. You might even be able to get small carpet samples for free, so you can try this idea out to see if it suits your style.
  12. hevans1944

    DIY high precision linear pot. Cheap too if possible!

    Hmmm. You did say DIY? If you can make one with your specifications for $15 you should become the richest Aussie in the world, practically overnight. I know I would buy a half-dozen of them. Seriously, for accuracy and precision over a ten-inch range of motion you need good bearings and a linear...
  13. hevans1944

    Controlling a UK mains supply from a Raspberry Pi Piface

    I think I would add a de-bounced push button switch, wire-or'ed with the optical isolator, to allow manual toggling of the flip-flop without using the NFC device. This just for test purposes, perhaps mounted on the circuit board, concealed by the metal case, and operated by a straightened-out...
  14. hevans1944

    Controlling a UK mains supply from a Raspberry Pi Piface

    Yes, pulsed ON followed by pulsed OFF is an extra complication. The whole idea behind moving hardware functions to software functions is the ability to make minor changes in software, which should be less expensive than creating new hardware solutions. Not saying it can't be done, but why go to...
  15. hevans1944

    Controlling a UK mains supply from a Raspberry Pi Piface

    The relay you select to switch the mains will depend on what kind of load it switches: resistive, inductive, incandescent lamps, switching power supply (e.g. computer), etc. The type of load affects the type of contacts used. The relay manufacturer's datasheet should specify the type of load the...
  16. hevans1944

    Sprinter's timing circuits

    I found a free web app that appears to do what you want. It records an elapsed time from START each time the SPLIT button is pressed. Could maybe run this from a tablet? Oh, and welcome to Electronics Point. You have found the right place for this sort of question.
  17. hevans1944

    Hello from Arizona

    There are no dumb questions, but there are plenty of dumb answers. We try to avoid the dumb answers here. Welcome to Electronics Point, Todd.
  18. hevans1944

    Question on assembly code

    Sounds like a good way to learn about the hardware. I visited my alma mater yesterday and decided to drop in to the UD Bookstore, just to browse among the new and used text books to see if there was something I might like to study. There was a shelf with texts on operating systems programing...
  19. hevans1944

    Question on assembly code

    Well, what exactly do you want to use your "new" computer to do? The 8088 is basically the same as the 8086, but with an 8-bit external data path instead of 16 bits. Both address 1 MB of memory in "real" mode. For "IBM-compatible" PCs, the 8088 was first replaced by the 16-bit 80286 for the...
  20. hevans1944

    Old RS-232 compatibility with new computers?

    There are a few things you can still do. Make sure the pins on the DB-9 connector are properly jumpered: pin 4 (DTR) or Data Terminal Ready should connect to pin 6 (DSR) or Data Set Ready; pin 7 (RTS) or Request to Send should connect to pin 8 (CTS) or Clear to Send. Then use a multimeter to...
Top