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  1. sureshot

    You tube channels.

    Quit liking you tube tutorials and similar. Can anyone suggest some good author hosts ! For the moment I have exhausted all of Dave Jones videos on the eevblog. Any other channel suggestions appreciated, thanks for reading.
  2. sureshot

    adding fans and heatsinks to components

    Most of your consumer electrical gear is well designed when it comes to cooling. If it ain't broke don't fix it is good advise ! But if you really feel extra cooling is needed, be sure to select the appropriate Voltage rail AC/DC etc, and you can always slow the fans speed with a series...
  3. sureshot

    Transistor hfe

    I think i got most of that, i will reread again, my memory is naff on med's (illness) but yes thank you Adam ! I will have to mock up a single transistor board version to try this. Really i might just get a breadboard, its long overdue. Since then i have tried 4 x TIP2955's with very good...
  4. sureshot

    Can anyone identify this type of connector?

    If the male and female measurments are the same as generic recepticles you probably could use them. Although another plug or socket from a scrap vheicle would be equally fine. Just use shrink tube over the soldered wires. Still be a tidy job.
  5. sureshot

    Transistor hfe

    Ok Adam Thanks for that.
  6. sureshot

    Transistor hfe

    This is interesting, although my knowledge base is limited, i do understand what is going on. I've put out questions in other areas before you started the simulations, and the wise grey beards say the same and similar theorys. But no one has took this far, so thank you for this. I'm interested...
  7. sureshot

    Transistor hfe

    Thanks for doing this Adam. So it needs some unwanted frequency removing during start up. This makes sense, as i thought nothing of this at first, but when i added and removed loads with both resistor base values, i noticed some odd noises coming from the fan. It was not constant, but would...
  8. sureshot

    Transistor hfe

    yes that would be very interesting if you have time to put a working model together. Thanks again.
  9. sureshot

    Transistor hfe

    Thanks Steve. I will have to put another test circuit together. There is only so far you can breadboard on veroboard lol, its not constructed for that. I've cast a net far and wide, and the general view is these high power darlingtons are best versed in a closed loop circuit with some feed back...
  10. sureshot

    Transistor hfe

    I think maybe there is oscillating going on maybe, but wih no scope i can not confirm that. I've a strong feeling this MJ11015 transistor is not best suited to this application. Its internal structure i think means it will behave badly in this emitter follower type circuit. I can't see any...
  11. sureshot

    Transistor hfe

    Well after some more testing i'm even more puzzled. No load on the output for the following. 100 ohms base Volts across it, 0.55 Volts output will not come down below 17 Volts. 24 ohms base Volts aross it, 144.2 mV . Its unstable at light loads, gaining at least 2 Volts with a 20 watt load...
  12. sureshot

    Transistor hfe

    I have over looked some thing... Whilst, and all the readings i have taken, where with the cooling fan running with its 47R series dropper resistor.. doh, looks like i've got to remeasure with it disconnected. A compleate oversight on my part.
  13. sureshot

    Transistor hfe

    Thank you Adam. Theory only nothing solid, but i think 100R is to high to get the transistor conducting forward properly. With 100R i think its bypassing the regulator leaving it vertually redundant, otherwise if it was functioning it would regulate that 12 Volt output. With a 24R value for R7 i...
  14. sureshot

    Transistor hfe

    So open the circuit on the input side of the regulator and measure in series idle no load ? Does that sound right. Not sure how it will help in getting that 17 Volts output down. But i suppose it will show if the regulator is contributing to the not so regulated output. I doubt it is...
  15. sureshot

    Can anyone identify this type of connector?

    They look like a variant of 4mm spade type recepticlesl, which might well fit. Worth a try, all or most electronics suppliers sell these crimp on type male and female connectors. Also come in 6.3mm sizes.
  16. sureshot

    Can anyone identify this type of connector?

    Looks like some kind of custom double row molex male and female connector. What is it from ?
  17. sureshot

    making diy transformer

    I have reused MOT's microwave oven transformers by rewinding the secondary. But there very inefficent. Don't do what you plan to, the only green you will see is in the cemetery. Not worth the risk.
  18. sureshot

    Transistor hfe

    Not the best pictures, but 5MP is the best i have at the moment. I doubt the solder side can be traced out easily, as i have moved some leads on previous resistor tests.
  19. sureshot

    Transistor hfe

    Well i have some numbers. I can't load the output at 17 volts, i don't have enough sacrafical lamps. R7 100R base, 0.1R 10W power resistor: Base resistor across it 1.02 Volts. Power resistor 16.7mV. R7 100R, base resistor. Power resistor 1R 10W. Base voltage across the resistor, 1.21 Volts...
  20. sureshot

    Transistor hfe

    yes Adam sure, that's not a problem. The underside of the veroboard has a few alterations since i started it, veroboard makes a poor breadboard lol. I can only get pictures to upload on the pc, so will do that later today if i can. Yes i totally agree with your opinion on creating a useful...
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