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  1. KrisBlueNZ

    USB ownership?

    If you're selling it, unless it's been formally approved, you shouldn't even IMPLY any compliance with the USB standard, or you risk getting a nasty cease and desist letter. I would explicitly say it's not type-approved. Unless you're a no-name fly-by-night Chinese manufacturer - they seem to...
  2. KrisBlueNZ

    Looking for a small, low rpm, higher torque motor. Help please?

    Oh yeah, you can use PWM if you don't need high accuracy or if there's speed feedback from the motor to control a servo driver. I think you would want a gearbox though. I missed your comment about 19V. As donkey says, that sounds like a laptop power supply. You could drop it down to a fixed 12V...
  3. KrisBlueNZ

    Looking for a small, low rpm, higher torque motor. Help please?

    Hi and welcome to Electronics Point :-) Sounds like you need a stepper motor with a gearbox. Controlling motor speed with a potentiometer is inaccurate, especially if the load varies. A stepper motor can be controlled precisely for any speed you want, though you'll need a suitable stepper...
  4. KrisBlueNZ

    Need help identifying problem with Logitech Computer Speakers.

    And show us closeups of both sides of the board in the area of the D-15 connector you want to replace.
  5. KrisBlueNZ

    USB ownership?

    AFAIK and "I am not a lawyer but...", you can do whatever you want as long as you don't try to market an unapproved product that you claim to be a USB product or that carries the USB logo. The name and logo are trademarks (probably a registered trademarks) of the USB consortium (or whatever...
  6. KrisBlueNZ

    Using a Varistor to solve a back EMF problem

    Also, I have no experience with this, but I suspect the best way to increase the contact life would be to reduce the rate of switching, by using a pressure switch with a wider hysteresis deadband. I think this is what Stu meant in post #1: "Square D switch. This will ensure a usable pressure...
  7. KrisBlueNZ

    Project Problems! Need guidance.

    Also post some photos of your coil assembly.
  8. KrisBlueNZ

    Solar charging LEDs ?

    Yeah, I guess so. When you turn the lights out to admire the little pinpricks of coloured light decorating your christmas tree, you aren't interested in how much illumination they provide!
  9. KrisBlueNZ

    Can I use a resistor as a fuse?

    I'm still following this discussion and interested in what Keysight say. So is that their final answer - they're unaware of "zero ohm resistor" in their products?
  10. KrisBlueNZ

    Problem with simple Power Supply project

    As Harald said, the +15 rail will be forced to sink current coming from the +30V through the positive side load. Power supplies are not normally designed to sink current into their positive outputs, since they are only ever used to source current. Also if the adapter has a connection from its...
  11. KrisBlueNZ

    Using a Varistor to solve a back EMF problem

    You didn't say where you're located, nor who your local retailers are. So I checked Radio Shack; they only have one varistor and it's designed for 115VAC mains protection. If you have any other local retailers, check their web sites to see what varistors / MOVs they have. I doubt very much that...
  12. KrisBlueNZ

    Solar charging LEDs ?

    Hi Owen and welcome to Electronics Point :-) No. It's those pesky laws of physics again. Even with the most efficient LEDs and solar panels you can get, you would need a large solar panel to produce enough energy from one day's sunlight to illuminate a sign for several hours.
  13. KrisBlueNZ

    Using a Varistor to solve a back EMF problem

    Hi there and welcome to Electronics Point :-) Were you trying to buy that varistor directly from Littelfuse? If so, you may find Mouser is a better source, though their shipping rates can be pretty high as well. They have that part in stock...
  14. KrisBlueNZ

    lm317 sub?

    Yes, and yes. You can construct the current sense resistor from a fixed resistor of 1.5Ω (to take most of the current) and a 20Ω trimpot (using the wiper and one end) in parallel, for fine adjustment. Alternatively, you can use the 1.5Ω fixed resistor, connect a 100Ω trimpot aross it, and feed...
  15. KrisBlueNZ

    television freq scanning

    Read post #3.
  16. KrisBlueNZ

    Massage chair control board help..

    The smoothing capacitor on the output of the bridge rectifier is rated for 25V according to your diagram, so I guess the voltage will be more than 8~9V but not sure how much. So is that the transformer that was exposed to the 220V AC? If so, you'd better check the output voltage. The "hybrid...
  17. KrisBlueNZ

    Need new mini DIN plug for Dell Harmon Kardon Hk395 speakers

    I've moved this question to a new thread. You need a mini-DIN plug? Is this one suitable? http://www.digikey.com/product-detail/en/MD-90/CP-2090-ND/145326 You may be able to get it elsewhere as well. What's your location? (You can put it in your profile.) What electronic component stores are...
  18. KrisBlueNZ

    Chicken Coop Door Opener

    Yes, but it might be best to run three wires instead of just two. For example, stereo audio cable with a single screen.
  19. KrisBlueNZ

    Hall Effect Latch Help

    Right. As Steve explained, the sensor has an open collector output and cannot drive its output positive. It can only complete the circuit between the output pin and 0V (negative supply pin). So you have to connect the LED between the output pin and the positive supply. Take that circuit...
  20. KrisBlueNZ

    Power issues with latches

    That's the 4043 that I mentioned. The only difference is that the 4043 has active high set and reset inputs, and the 4044 has active low set and reset inputs. Active low inputs are more common in the 74xxxx devices; most 4000 series devices use active high logic. But I don't think it really...
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