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  1. chopnhack

    Designing a Time Delayed Relay

    I figured if I had a BOM first, I could use it as a ways of checking against the schematic looking for discrepancies. Later it helped me as a check list when I was looking for the physical sizes to ensure that I was using the correct models in Eagle for the board layout! I will start later...
  2. chopnhack

    Designing a Time Delayed Relay

    Ok, draftsman, I am not! LOL, thank you for the information - Eagle is not the easiest program to work with, but most of the corrections are of my sloppy work so I take credit for that myself ;-) I have fixed most if not all of the above, to make it more readable. I omitted the data initially...
  3. chopnhack

    Looking for a mentor

    Very well said, Adam :-)
  4. chopnhack

    Designing a Time Delayed Relay

    Thanks Kris! I guess I over thought the bridge connections. When I was trying to figure out the connections, I really should have resolved the original schematic to the 4 points, AC L1, L2 and Pos, Neg - instead of the way I did it. As soon as I saw your revision, I understood that it was simple...
  5. chopnhack

    Looking for a mentor

    Check out the post below Kevin, I have found it to be very useful so far. Also, by posting your questions on this excellent forum, you will receive help. Do your part to ask detailed and intelligent questions - search the web first, read some articles on this site, peruse the growing resources...
  6. chopnhack

    Designing a Time Delayed Relay

    Temporarily picked a few connectors to finish the schematic. Could you look it over for any errors? I had a bit of a struggle with the bridge rectifier until I started to think of the nodes! Please let me know if you see errors, I will start on board layout next. Thanks!! Sorry - the quality is...
  7. chopnhack

    Designing a Time Delayed Relay

    Awesome! I did use a separate viewer for the schematic, but it was still blurry, thanks for confirming that. The bridge diode is smaller and certainly more compact than the individual diodes. The additional smt components decreases the layout flexibility some as there are fewer opportunities to...
  8. chopnhack

    Designing a Time Delayed Relay

    Is it ok to substitute this bridge rectifier in place of the 4 1n4004 diodes? D1-D4 http://www.digikey.com/product-detail/en/DF04S-G/641-1345-5-ND/2074810 Also, what is the value of R9? I can't quite make it out - either 8.2 or 9.2k?
  9. chopnhack

    Why was this equation required to be in metres before resolving?

    Thanks Merlin, I didn't catch that.
  10. chopnhack

    Constant current power supply

    Have you had to create any of your own components with Designspark? Is it easy to do? How do you like the program overall?
  11. chopnhack

    Designing a Time Delayed Relay

    LOL, indeed! If the darn thing won't fit in the boot, it doesn't come home! ;) Perhaps the 6 pin per Allegro, if it will fit, that should give us some headroom for full load when the motor is turned on. I think this should be a very interesting layout. I will try to workout on that tomorrow!
  12. chopnhack

    Designing a Time Delayed Relay

    The header might save some space, the cost is probably around 3x more. Why were you saying to switch to 6 or 4 pin now? The current to the Allegro's is still the same.
  13. chopnhack

    Designing a Time Delayed Relay

    The connector itself is soldered to the board, while the incoming wires are fed into the channel below and a screw (from above in this picture) forces a bar down onto the wires. Fairly small units, but there are of course other options.
  14. chopnhack

    Designing a Time Delayed Relay

    I think back in post 77 you used a 8 pin and a 6 pin header with plug assembly - 4 pins per leg of the current circuit to the allegro chip. I don't know what space I will have, but if I run into constraints those certainly will help! I was think of using the phoenix combicon compact screw...
  15. chopnhack

    Constant current power supply

    Lamma, what software are you using for your board layout/schematic?
  16. chopnhack

    Free MIT course on Circuits and Electronics

    LOL, well played ;-)
  17. chopnhack

    Free MIT course on Circuits and Electronics

    Excellent Adam! Now I can pester you for help :-P
  18. chopnhack

    Why was this equation required to be in metres before resolving?

    And therein lies the rub! The text did not cover resistivity or define it, but now I understand the why. As Merlin points out, resistivity has units - Ω/m and that is why I was off by an order of 3. I saw that I had the same number, just the wrong decimal point. Key to remember is keep track...
  19. chopnhack

    Free MIT course on Circuits and Electronics

    Awesome Steve! I hope more people take advantage of it :-)
  20. chopnhack

    Why was this equation required to be in metres before resolving?

    I used Resistance = Resistivity * Length/Area, but used millimetres. Resistivity will equal P for simplicity in writing out the equations online. R=P*(5mm/pi*0.25) R=P*5mm/0.785 R=P*6.36943 1 ohm = P*6.36943 divide out the 6.36943 to get resistivity of material is 0.156999 for that size...
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