Search results

Search Forums New Posts
  1. (*steve*)

    Measuring battery voltage with an MCU while charging and discharging

    Using n channel MOSFETs like that will require a gate voltage of about 30V to turn them on. I would recommend you use a p channel MOSFET which can be turned on by pulling the gate toward ground. You will have to make sure you don't exceed Vgs(max), and that you don't try to source current into...
  2. (*steve*)

    "Is" value, or "reverse saturation current" of a PN junction, how to get it?

    If you are designing your own semiconductor device you'll have access to this information and you can use it to calculate the expected values. This, along with other details allows you to predict the performance of the device, predicting what will appear in the datasheet (actually it's likely...
  3. (*steve*)

    Measuring battery voltage with an MCU while charging and discharging

    During charging the battery voltage will be the charger voltage. If you want to measure the battery voltage whilst it is not under load (the charger represents a type of load -- albeit one that has a negative power) then you need to disconnect or otherwise disable the load.
  4. (*steve*)

    Making a Pulsing/Fading LED Circuit

    As long as the thread is: Still discussing the original problem effectively Remains friendly Doesn't evolve into Woo-woo I have no problem with parts (even large parts) of individual posts following interesting sidetracks. At the point where either of the above cease to be the case then I...
  5. (*steve*)

    Holiday pics

    The next two "random pictures of an Australian City" were taken at dawn as we entered the Port of Melbourne. I was not expecting hot air balloon, but hey, there they were. There next two pictures were taken in Hobart on the Derwent River on the way to Mona (a relatively famous art gallery)...
  6. (*steve*)

    Ir break beam help

    Yeah, I'd say the IR LED is backwards too.
  7. (*steve*)

    Holiday pics

    The first 4 pictures were taken at the site of the old visitor's centre at Port Arthur. This was the site of many of the deaths in one of Australia's best known multiple shootings. This event was the one which prompted the then-current right leaning government (with strong public support) to...
  8. (*steve*)

    PCB Connectors

    There are multiple options from pin headers to terminal blocks.
  9. (*steve*)

    AC 18650 Replacement?

    I think it's fairly safe to assume that the flashlight has already been used at least once and did not explode. Hence, one must assume that a constant voltage source of about 3.6V is going to safely power it. The remaining question is there required current. If the OP can't or won't measure...
  10. (*steve*)

    How to block Magnetic field coming from substation and underground power to property beside it

    That will be extremely effective. After building that fence I am sure you will no longer be affected by the magnetic fields.
  11. (*steve*)

    K40 Laser Cutter Upgrades

    I'm struggling to comprehend what they're doing with the lens on this thing. It must be totally unprotected. Yeah, I would get a head like the one you suggest. Also note that there is air on only one side of the lens. Bleeding some air into the other side will keep the upper side clean. You...
  12. (*steve*)

    How to block Magnetic field coming from substation and underground power to property beside it

    And imagine the sudden death which might occur if you were subject to a three Tesla magnetic field!!!!
  13. (*steve*)

    K40 Laser Cutter Upgrades

    Some of the things I would do or consider: Get an aquarium air pump and use it to direct air over the mirrors. This will keep them clean. Get some airflow (any at all) through the air-assist connection. It doubles as a coolant for the lens and helps stop dirt getting on the lens (a major...
  14. (*steve*)

    Mosfet gate voltage

    In general a higher gate voltage DOES give you a lower source to drain resistance. However this resistance is constant only at currents up to a certain point. Tell me what mosfet you're using and we can take a look at some of the stuff in the datasheets and explore what the mosfet can do...
  15. (*steve*)

    CRT television not working anymore.

    Yes. There are capacitors which can hold a charge for quite some time after the power is removed. Whilst they're unlikely to kill you, your reaction to getting shocked by them can cause you to do damage to yourself or the thing you're repairing. Leave it an hour or so and you should be fine...
  16. (*steve*)

    Holiday pics

    OK, back to Australian cities. This one should be easy... (yeah, we were on a fairly big boat) Need more clues? And yeah, it was the Gay & Lesbian Mardi Gras the evening I took this image. And there were a few people on the water flying the flag! (And possibly...
  17. (*steve*)

    Holiday pics

    As several of you are aware, I had a small holiday at the beginning of this month. What follows are some highly political images taken during that holiday... And now some that are less challenging for parts of our international audience... And some random...
  18. (*steve*)

    CRT television not working anymore.

    My guess is that there is now a power supply fault. Beware that CRT television sets have very high voltages inside. I'd strongly recommend you get someone qualified to look at it unless you're comfortable (and safe) working around high voltages.
  19. (*steve*)

    Where did the - 0.7 V from the graph came from? (Diode Clampers Circuit)

    The simple answer is that when forward biased, the anode if a diode is always a little bit (0.7V for a silicon PN junction) more positive than the cathode. In the diagram you showed, the reference point is the anode (it is ground) and so, with respect to that, the measured point (the cathode)...
  20. (*steve*)

    Mosfet gate voltage

    Just a technical point. What you want is exactly NOT to have the mosfet in saturation mode. When a MOSFETs changed is saturated, it is effectively operating in a constant current mode with a large voltage drop. You want the mosfet to be operating in its triode region where the channel...
Top