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  1. CDRIVE

    How to modify 12-24v car phone charger?

    8.75V is pretty close but if you need a bit more voltage you do have one more diode left that you can add to the series string. This will bring the output voltage up to about 9.5V. I'm referring to the bottom diode (D1) in your last photo of the foil side of the board. It's currently connected...
  2. CDRIVE

    How to modify 12-24v car phone charger?

    Personally I like solid wire for this kind of work. Small gauge too! Telephone or CAT5 or 6 even better. The stuff I really like has Teflon insulation that melts at a much higher temp than most common insulation found on small gauge wire. I also like a 'hot' iron that gets me on and off the...
  3. CDRIVE

    How to modify 12-24v car phone charger?

    This is just an FYI and is not implying that Ed's method of increasing an LM7806 output voltage to 9V by added Diodes in the 7806 GND leg is wrong. After all, many of us have been using this method successfully for decades! That's why I was very surprised to see that my Fairchild LM78xxx...
  4. CDRIVE

    2 leg 2.1mm DC socket use in a circuit.

    If he can find empty real estate I guess he can add a Diode as a safeguard. Chris
  5. CDRIVE

    How to modify 12-24v car phone charger?

    I just noticed that your board employs 5 series Diodes that drops the input voltage to the regulator by (.7V * 5) = 3.5V. Therefor if the battery voltage is at 12 volts then 12 - 3.5 = 8.5V inputted to the regulator. You will probably have to jump some (possibly all) of these diodes to keep the...
  6. CDRIVE

    How to modify 12-24v car phone charger?

    The LM78xx series regulators can output up to 1A with proper heat sinking. Keep in mind that the heat dissipated by these regulators is related to both the input voltage and the output current. The max input voltage of the LM78xx is 35V with the exception of the LM7824 that has an input max of...
  7. CDRIVE

    Building a current source

    For some odd reason it never requires the skills of Columbo to deduce when a topic is homework. :D Chris
  8. CDRIVE

    GPS NMEA, Failover Circuit upgrade attempt.

    On the 14M2 physical Leg 2 (C.5 Serial In) is the Program Download pin. It can be used as a Serial RX pin but with caveats. The Picaxe PDF manuals cover these issues. For complete descriptions of these commands refer to the PDF Manual 2 (Basic Commands). hSerIn SerIn SerRxd Chris
  9. CDRIVE

    Building a current source

    Hop, I have suspected for quite some time now that there are burn marks on your keyboard. This from a semi hunt and peck typist. I'm jealous! :p Chris
  10. CDRIVE

    2 batteries selector

    Fig12 & Fig13 of the ICL7673 Datasheet shows a typical low & high current circuit that includes hysteresis. Chris
  11. CDRIVE

    Need help selecting a transistor for a large power load

    The 1N4002 are power rectifiers and are also commonly used for relay coil kickback suppression. Chris
  12. CDRIVE

    How much of a Short circuit is too much?

    I'm glad to hear that you solved your problem.... At least I think I am? Have you considered the dangers involved with wireless firing devices? If this was my project (doubt it), power to this board would be preceded with a timer circuit that would provide more than enough "Get the F!ck out of...
  13. CDRIVE

    Building DIY Vacuum tubes

    George, I like it when we know a member's name instead of only a handle. That said I hereby dub you 'MacGyver'. We have a member (Miguel Lopez) that lives in Cuba. What most of us find common and easy to obtain are unreachable for him. If you lived on the island you would be his best friend...
  14. CDRIVE

    Building DIY Vacuum tubes

    When I read the title to this topic I involuntary rolled my eyes:rolleyes: in anticipation of reading a nube's over ambitious attempt to do something far beyond their understanding and capabilities. How wrong I was! I can't speak for everyone here but these are some of the emotions this thread...
  15. CDRIVE

    555 IC not amplifying enough

    This really sucks. At my age my doctor wants me to have general checkups every six months. Since I hate those lectures about cutting back on alcohol and carbs I dry myself up three weeks prior to my visits. With that fact in mind I think I'd do better understanding this thread ....before I...
  16. CDRIVE

    Building my own bench drill

    Well you have access to editing or removing it. Why wait for the mods to do it? Chris
  17. CDRIVE

    Building my own bench drill

    Thanks for posting the rack side of that shaft but it leaves me even more confused. I expected it to be hollow to accept the rotating spindle that holds the chuck at the bottom end and the pulley at the top end. On another note I accidentally clicked on the first image you posted in this post...
  18. CDRIVE

    Tilt and swivel antenna mount

    Perhaps there are off the shelf (out door) panning mechanisms intended for security cams that could be adapted? Chris
  19. CDRIVE

    Control large stepper motors

    It's rare that I will disagree with Hop but IMHO "Electronics Point" should be the first hit that Google returns! :) Chris
  20. CDRIVE

    Industrial switches project

    A capacitor is not used as the basis for latching relay circuits or solid state equivalents. Chris
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