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  1. (*steve*)

    Interpupillary Distance Adjustment on a Microscope Impossible?

    Well, the theory is that you adjust the microscope until it works for you. I also have problems with binocular microscopes, and I have been known to just close one eye. Binocular microscopes are not stereoscopic so if you close one eye you don't lose information.
  2. (*steve*)

    How to change LED flashing?

    The last one of those LED flashlight modules I took apart (and it was a long time ago) used a small 8 pin PIC which was flash programmable (I.e. not a OTP device). A more recent board that I've seen (but not examined in great detail) used a chip with a similar pin count but could not be...
  3. (*steve*)

    A Current Balance Circuit for LED Strings in Parallel with Polyswitch Protection

    If LEDs are on the same heatsink it will act to reduce the temperature difference between them. The closer the temperatures of two strings can be maintained to each other, the smaller the potential drift in the sharing of current between them will be (assuming they are similar devices and we...
  4. (*steve*)

    Help with DC / DC boost controller chip

    If you had mentioned you were using anything other than direct sunlight... Anyway, I'm glad it's working for you now.
  5. (*steve*)

    Help with DC / DC boost controller chip

    If you connect your panels to the boost converter with no load connected to the boost converter (and the cells in full sun)... what is the voltage at the input of the boost converter? what is the voltage at the output of the boost converter? edit: make sure the cells are in full sun BEFORE...
  6. (*steve*)

    Crafstman Lawn Tractor Reads 35VAC Across Battery

    So now the story changes from voltage measurements are not enough: to It's really hard to measure the current: ...and it's AC to it's not DC and it's not AC: to you can't even measure it: not even with a low value shunt: to You can only measure it one way (with a low value...
  7. (*steve*)

    Crafstman Lawn Tractor Reads 35VAC Across Battery

    I guess Colin has just undiscovered flux gate magnetometers. Or perhaps because they're so new Colin's not aware of them. I'm sure he'll come up with another reason he's right though. He always is.
  8. (*steve*)

    Crafstman Lawn Tractor Reads 35VAC Across Battery

    OK, what about a DC clamp meter that can correctly read a signal with up to a couple of kHz AC on top of it?
  9. (*steve*)

    Converting 6v power wheels to 12v

    Either go back to a 6V battery or change the motor for one that is happy with 12V. If the are any other electronics (how does it's throttle work?) Then this should also be reviewed and possibly replaced.
  10. (*steve*)

    Converting 6v power wheels to 12v

    It's probably a thermal cutout. You're lucky it has one.
  11. (*steve*)

    Crafstman Lawn Tractor Reads 35VAC Across Battery

    What about using a clamp on DC current meter Colin?
  12. (*steve*)

    Battery charged by a solar panel?

    I have a colleague who charges lipo batteries this way (in a sealed outdoor device). However he has a shunt regulator across the battery. This will work well for lipo's and possibly lead acid batteries, but not with nicad or NIMH batteries. You need to ensure that the charge current cannot...
  13. (*steve*)

    Help with DC / DC boost controller chip

    You have discovered the main difference between MPPT and a SMPS. MPPT will deliver as much power as possible to the load. An SMPS will drag the input voltage down if the entire damanded power cannot be supplied. Where there is excess input power, both will work. If the available power...
  14. (*steve*)

    Can an old Ni-Cd battery charger be used for Ni-MH batteries?

    That may work if you discharge the batteries completely and know their storage capacity with some accuracy. Going for an 80% charge is probably safe. If the cells get hot you've exceeded 100%
  15. (*steve*)

    Brick-and-Mortars For Electronic Parts

    What are these "brick" things, and why do they sell stuff?
  16. (*steve*)

    Wiring LED Lights

    Go to our resource section and read the one about driving LEDs.
  17. (*steve*)

    Segate 2TB HD

    Most often the power supplies for these supply BOTH 5V and 12V.
  18. (*steve*)

    Can an old Ni-Cd battery charger be used for Ni-MH batteries?

    No. It will not detect the end of charge.
  19. (*steve*)

    Could a consumer electrical power meter measure power used by a dehumidifier?

    If it can report power factor then it should be fine for reactive loads.
  20. (*steve*)

    A Current Balance Circuit for LED Strings in Parallel with Polyswitch Protection

    So much to answer on a phone! (Beware autocorrect errors). Unbalanced LED current in parallel strings. Let's assume you have two strings of perfectly identical, perfectly matched LEDs on identical heatsinks in the same environment, but running quite warm. Initially they will draw the same...
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