Search results

  1. O

    How can I calibrate a scope?

    Honestly, I haven't had the manual out in 10+ years, but the basic tools you need are a DVM, a scope, a high voltage probe, among others.  I never did my scope because of the needed tools.  My company I USED to work for refused to do their own scopes, so they had them sent in.  I don't think I...
  2. O

    Aaaargh! 555 circuit works well with LEDs but not with relays...

    Bmachine, Sorry about the drawing.  Had I known that you were a real newbie, I'd have added the base resistor to the transistor, the current limiting resistor to the LED, and etc., but I see that Audioguru has it under control.  The intent of the drawing was to give you ideas for you to design...
  3. O

    How can I calibrate a scope?

    Not knowing a lot about the scope you are going to purchase, and considering you views on accuracy, 2 of my past Tektronix scope's and my BK Precision have a 1khz squarewave calabration timebase output to check the probes, and accuracy check.  If this is the closest to accuracy you want, then...
  4. O

    Aaaargh! 555 circuit works well with LEDs but not with relays...

    Hello all, I was always taught that I should drive a passive part with a transistor. (old school) I have included a quick drawing.  I drew it because I don't know Bmachine's background, and Audioguru's explaination could be a little confusing to a newbie.  The Damper Diode (supression diode)...
  5. O

    Auto/deep cell charger

    MP, Makes more sence that what I've been running into. 1000pF=1nF 1000uF=1mF Etc. Just have to remember to convert and re-convert before I look for parts in my suppliers manuals,
  6. O

    Downloading error

    The error is simple...... If, for any reason, your download is interrupted, you cannot "resume" where you left off.  You must start from the beginning of the file to download it.  Download manager programs will not help here, as the program provider does not support it. oldgrandpainmi
  7. O

    Electricity Meter

    Raccoon, I'd build it, just for the fun of it!  There is allways a better feeling saying "I built it myself", than "I bought it"!!! Besides, as you learn the circuit, there will be a little voice in you head that will say "Maybe it will be better if I .........."!!!!  Then you can say, "Mine...
  8. O

    how to build my own buzzer? (or other noise maker)

    Sarah, If you take awright's advice (which is great), I'd advise you to keep an eye out for some old computer motherboard's at flea market's, garage sales, etc., and strip off the speakers from them to use.  They can easily be desoldered and used in the circuit you are using.  Besides, the cost...
  9. O

    Air core inductor forms

    Hello all, I hope you can give me advice/information an where I can get some coil forms for construction of a 1mH and .22mH air core crossover inductors.  Yeah, I could buy them a lot easier from a couple sources, but I'd like to see if I could build them for fun, first!  I had been hoping to...
  10. O

    Difference between 5/7/12mi range radios and leveling the playing field...

    Shelby, I didn't go thru all of that with the iron.  Just replace the tip locking screw with a longer one and use it to clamp the needle into place.  Nothing else needs to be done.  When done you can replace the needle with a new (or old) tip. oldgrandpainmi
  11. O

    Auto/deep cell charger

    I got a reply from the author. Yep, a nonofarad (n) = a nanofarad, but a Microfarad (m in Europe) = uF U.S.!  I figured that if they used a different symbol for Micro, then they would have used a different for Nano, which isn't the case.  Thus the confusion. Also, L1 is a .22mH (220uH) not a...
  12. O

    Difference between 5/7/12mi range radios and leveling the playing field...

    Hello all, Just my 2/100 of a dollar! If a small enough soldering tip can't be found or made, what I've done in the past is to get a cheapy, dual wattage, iron from Radio Shack.  It has a screw in tip with a set screw to lock it.  Remove the tip and insert an leather sewing needle.  Break it...
  13. O

    Auto/deep cell charger

    Ante, I downloaded your circuit and will look at it further this evening. I did notice that the primary voltage is 230vac at 50hz.
  14. O

    Auto/deep cell charger

    Kasamiko, I just got home from work and looked for your reply, then it hit me!!! For the example I used, a 100mF cap = .1uF ,
  15. O

    Surplus Crossovers

    Hotwaterwizard, I may be interested in a couple. I am looking for 2 crossover inductors of 1mH and 1 of .22mH.  Are the inductors in your crossovers eather value -or- do they have a part number that I can look up? oldgrandpainmi
  16. O

    Auto/deep cell charger

    Kasamiko, Thanks for the artical.  It is the same basic idea I have used for NiCad's for years.  (Charge a cap and discharge it to the battery).  But you have to remind me about the capacitors.  They are listed (for example) 100mf and 10nf.  I know this is not what they actually are, as a 100...
  17. O

    Auto/deep cell charger

    Hello all. I understand the difference between a standard lead/acid automotive battery versis a deep cell lead/acid battery.  What I would like to know is the actual difference between the corresponding chargers.  I run deep cells while fishing, and am aware that using a standard charger will...
  18. O

    B type tapers

    Mares, I am hoping that "tapers" are the same thing as a tap.  My opinion is that if you are designing a mechanical "adaptor" for a tap, go to a machinest forum.  They specialize in this subject and are as helpful as these guys are with electronic questions in this forum. oldgrandpainmi
  19. O

    Difference between 5/7/12mi range radios and leveling the playing field...

    SM2GXN, My call is W8BAJ. oldgrandpainmi
  20. O

    Difference between 5/7/12mi range radios and leveling the playing field...

    For sake of discussion only? The EASIEST way to increase the range is to change the antenna!!! As a ham operator, an antenna is called "the poor man's amplifier", regardless of output power.  Here's why: If your antenna has a 3db gain your ERP (Effective Rated Power) is about 2x the amp...
Top