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  1. (*steve*)

    my power supply device rated 13.8vdc output but I've test it and the output voltage is 26.8vdc

    It's also possible that the 723 has been damaged. They have no protection. If excess current was drawn it is possible that the package dissipation was exceeded and the output transistor was destroyed. (Don't ask me how I know) :-(
  2. (*steve*)

    my power supply device rated 13.8vdc output but I've test it and the output voltage is 26.8vdc

    Is it something like this?
  3. (*steve*)

    Integration of Camera in Cathode ray oscilloscope (CRO)

    Back in the days before digital oscilloscopes these were common. There's no reason you can't do it today. In essence all you need is a camera with a short enough close focus for the display to fill the field of view. Many phones will do this today with supplementary close-up lenses. The...
  4. (*steve*)

    Battery eliminators for Smartphone devices

    You can eliminate the battery, but that will leave your phone without power. Phones tend to have the best batteries economically available. When better batteries are available you can bet the high end phones will be amongst the first to use them.
  5. (*steve*)

    Lead acid battery

    Flat means not charged. A 12V lead acid battery which measures as only 12V is very close to discharged. Sulphation is a problem with lead acid cells where the lead sulphate changes into lead sulphide (typically after being left discharged for an extended period). The battery loses capacity.
  6. (*steve*)

    Lead acid battery

    Your batteries are flat, have a dead cell or two, or are sulphated.
  7. (*steve*)

    Mimic a Type 80 rectifier tube

    Another issue is that the tube will have a higher voltage drop than silicon diodes. This will generally lead to a higher HT which may be a problem for the other valves.
  8. (*steve*)

    Greetings

    Hello and welcome
  9. (*steve*)

    Just murdered a MOSFET. What did I do wrong?

    The issue with diode speed is how fast they turn off, not on. (Assuming your not using PWM)
  10. (*steve*)

    Just murdered a MOSFET. What did I do wrong?

    I'm not sure what happened to my last post, but look here for a gate driver: http://www.piclist.com/techref/mimedecode.asp?url=piclist%5C2004%5C06%5C21%5C220147a%2Etxt&part=2 I've described this corrupt a number of times here. 12V would be best, but 6v should be sufficient. It's a bit of...
  11. (*steve*)

    Just murdered a MOSFET. What did I do wrong?

    Have a look in the resources section. There is a circuit in there which will allow you to drive your mosfet gate from a higher voltage (12v would be ideal, but you'll probably get away with 6v)
  12. (*steve*)

    Issue in BLDC motor

    Have you measured the latency between the detection of position and the changing of the state of the MOSFETs? How many μs is it?
  13. (*steve*)

    Issue in BLDC motor

    The reason I suggest using seq+1 is that one reason for the motor not going any faster is that by the time you've sensed the position and decided to turn on some set of MOSFETs, and then the MOSFETs turn on and off, the motor has moved far enough that you should already set the next position...
  14. (*steve*)

    Just murdered a MOSFET. What did I do wrong?

    You either need a logic level mosfet, a gate driver, or (probably "and") for you to read and understand the datasheet to some extent. A small gate voltage, as long as it's above the threshold voltage for the MOSFET, will allow it to switch a small load. For heavier loads, higher gate voltages...
  15. (*steve*)

    Identifying and replacing diodes??

    There are all sorts of diodes, and all sorts of applications for diodes in which different characteristics are important. Unless you know a side is faulty, replacing them all willy-nilly may just result in you introducing all sorts of subtle faults. What are you trying to do? Are these...
  16. (*steve*)

    Issue in BLDC motor

    Where does seq come from? And why is there a duty cycle involved? The main difference between a bldc and a three phase pm synchronous motor is that you supply a constant voltage to the windings for the period they are energised. What frequency is your pwm done at? Aside from being unusual...
  17. (*steve*)

    Magnifying lens help needed pls.

    A 50mm lens is a 20 diopter lens (just to pull Hop's post into tighter focus)
  18. (*steve*)

    Magnifying lens help needed pls.

    The use of a 50mm lens as a quick substitute for a loupe is an old photographers trick. It's not necessarily the best option, and it is more bulky and heavier than other solutions. 50mm lenses are usually good for this purpose because (at least in the past) were often double gaussian lenses...
  19. (*steve*)

    Voltage Reference

    I agree with your reading of that phrase in that context, but only because of what I consider to be very poor wording. If something is connected to ground it (ideally) has no (zero) voltage with respect to ground. I'm actually unsure of what the writer means by using that phrase. Perhaps they...
  20. (*steve*)

    Voltage Reference

    No. If you're talking about a car battery you might say that the positive terminal is at 12V referenced to the negative terminal. You definitely don't want to connect them together. Voltage readings are always relative to some reference point. The wording you're asking about is just telling...
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