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  1. KrisBlueNZ

    Transistors

    I think you probably can! I'm certainly not going to argue with you - my understanding of solid state physics is very limited. Is that how you would describe it? This is interesting. Recently I did some experiments (well, just LTSpice simulations actually) to try to delve deeper into the...
  2. KrisBlueNZ

    strong thermal glue for laptop DC power jack?

    Congratulations! Another usable bit of equipment rescued from going to a landfill somewhere.
  3. KrisBlueNZ

    Best basic electronics course

    Yeah, I remember seeing that post. Are you serious about "conclusive evidence" that the south pole is the "top" of the Earth? I didn't think it could be anything other than an arbitrary decision that went that way because the first map publishers lived on that end of the globe...
  4. KrisBlueNZ

    Temperature compensating a transistor?

    Right Steve. I suggested that in post #5, last paragraph, although I suggested using a BJT. You could also use a Darlington, or a FET of one sort or another, for better accuracy. I think that's the best way to get a (roughly) linear voltage vs. 1/f response. I did some simulations in LTSpice to...
  5. KrisBlueNZ

    Unknown part

    What do you mean "no pic"? I mean that you should take a picture of it. Does the 'F' look like the Fujitsu logo in this picture?
  6. KrisBlueNZ

    Best basic electronics course

    Not entirely. Down Under, where I live, the electrons go in the opposite direction. Something to do with the Coriolis effect I think ;) Kris .... if you use : and ) only instead of ;-) you get the wink icon :) Dave
  7. KrisBlueNZ

    Transistors

    Well, given that Vbe and Ib are clearly related, any circuit that can be explained in terms of one can be explained in terms of the other; it just depends which way is more helpful for understanding the component or circuit. In the case of a current mirror, the two transistors have the same Vbe...
  8. KrisBlueNZ

    Unknown part

    I've Googled that part number and it looks like it's made by Panasonic / Matsushita, and possibly Fujitsu. I can't find any data on those manufacturers' sites. Can you upload a photo of it? It may have a manufacturer's logo we can recognise.
  9. KrisBlueNZ

    Temperature compensating a transistor?

    OK, thanks for answering those questions. I can't suggest any way to improve the temperature sensitivity. The transistor is being used in a way it's not supposed to be used, and its gain will vary with temperature, as well as from one transistor to another. If you change the circuit to use a...
  10. KrisBlueNZ

    Transistors

    It's clearer to describe it as inversion. The signal comes out upside down. For many waveforms, such as a sinewave, a square wave with 50% duty cycle, etc, this corresponds to a 180 degree phase shift, but it's clearer to define inversion as inversion, not phase shift. Inversion refers to the...
  11. KrisBlueNZ

    Help please

    Hello and welcome to Electronics Point :-) My crystal ball was damaged by a power surge, so I'm afraid you're going to have to provide some information. Manufacturer, model number, photos of the board, description of what you mean by "bad", information on what was repaired in the past.
  12. KrisBlueNZ

    Transistors

    Agreed. You could say that any semiconductor is voltage-driven, because you need voltage to make current flow! From that point of view, LEDs are voltage-driven! But LEDs are characterised as current-driven, and BJTs are characterised as current amplifiers, because that's the simpler and clearer...
  13. KrisBlueNZ

    0.5 second monostable pulse??

    The diode won't cause a problem. Its cathode is connected to the positive supply rail. If it were round the other way, there would be a problem.
  14. KrisBlueNZ

    Temperature compensating a transistor?

    I'm really surprised to hear that. Can you clarify a few things for me? 1. What are the minimum and maximum control voltages at the transistor's base that produce that range? 2. Does a higher control voltage produce a higher frequency, or vice versa? 3. Is the schematic in post #4 an EXACT...
  15. KrisBlueNZ

    Transistors

    Both common emitter and common base configurations have voltage gain. Wrong again. Common base configuration is also non-inverting. Also wrong. BJTs are current-driven, but they also provide voltage gain. Input signal voltage is converted into a signal current by series resistance and/or the...
  16. KrisBlueNZ

    Temperature/pressure transducers

    Well, there are plenty of ICs that sense temperature. Some have a linear output that can be fed into an ADC, and some are accessed digitally. I've used the Dallas/Maxim DS1822 before; it uses the "one-wire" protocol and can measure from -55 to +125 degrees Celsius and costs a few dollars. But I...
  17. KrisBlueNZ

    C&I Practioner

    Great! Sorry, I didn't mean to cast aspersions on your practical abilities! I'm sure you'll be a valuable contributor here :-)
  18. KrisBlueNZ

    C&I Practioner

    Hi Charles and welcome to the Electronics Point forums :-) Your experience could be very valuable here, if you're prepared to answer questions and help folks with their control-related projects. This is not really an intellectual discussion site though; we're mostly hands-on and here to help...
  19. KrisBlueNZ

    Temperature/pressure transducers

    Hi and welcome to Electronics Point. You could start by Googling temperature sensor uk and pressure sensor uk and having a look at what's available. If you want advice on specific sensors and how they could be interfaced to an Arduino, post links to the data sheets for the sensors and we will...
  20. KrisBlueNZ

    switch helpQ!

    Here are some examples of switches that should be suitable. http://www.digikey.com/product-detail/en/GF-126-0318/CWI441-ND/4425726 http://www.digikey.com/product-detail/en/GF-126-0305/CWI348-ND/4089808 http://www.digikey.com/product-detail/en/GF-126-0288/CWI345-ND/4089804...
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