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  1. Arouse1973

    How a BJT Transistor works (base current version)

    I am with Lvw on this, it just does not make sense with respect to the physics of a BJT. I have done a simulation and my plot shows Ie increasing with respect to Vbe increasing. You have to get the scaling right to see it because the changes are so small. Your only talking 691uV change in Vbe. Adam
  2. Arouse1973

    Need help design UV Curing heads

    I must admit 100mW/cm seems quite small. I was thinking more of 4 to 8 Watts. Adam
  3. Arouse1973

    How a BJT Transistor works (base current version)

    Ok I guessed so much just checking. Please email me the sch, [email protected]. Thanks Adam
  4. Arouse1973

    Need help design UV Curing heads

    I liked your post so much I have asked one of my distributers to get involved and confirm my findings. They are one of the leading experts in optos, Osram. Lets see what they come back with. Adam
  5. Arouse1973

    Need help design UV Curing heads

    Pacer http://www.analog.com/en/switchesmultiplexers/analog-switches/products/index.html Adam
  6. Arouse1973

    How a BJT Transistor works (base current version)

    And the rise time and voltage, sorry forgot to ask that. Adam
  7. Arouse1973

    How a BJT Transistor works (base current version)

    Hi Claude I can't see clearly enough, but why have you added so much to the math to the waveforms. Adam
  8. Arouse1973

    Sensorless BLDC motor driven synchronously.....hrmmm...

    Cheers Fish, I have a read through over several ciders tonight. I won't reply then because I talk bollocks when I have been drinking, well that's what the misses keeps telling me :) Adam
  9. Arouse1973

    How a BJT Transistor works (base current version)

    Hi Claude What waveform shape were you using? Thanks Adam
  10. Arouse1973

    Need help design UV Curing heads

    Ok so I have had a go and as you would expect it's a bit more complex than you might think. I have given an example of a unit distance of 1 to indicate 1 unit of solid angle (Steradian) This can make approx. validation easier as without any losses. Example: A light source at a distance of 1m...
  11. Arouse1973

    Sealed Lead Acid Batteries

    There is nothing wrong with this as long as you ensure the charging current at the start is approx. 1/4 of the battery capacity until the absorption stage voltage is reached say 14.7 Volts. Then monitor the current until it's about 0.7% of the capacity and then switch over to float charge of...
  12. Arouse1973

    Constant current Source clarification

    You have no power to the current source transistor. Move the connection of pin 2 to the source of the FET Q1 and the connect VCC to the top of R1. Adam
  13. Arouse1973

    Need help design UV Curing heads

    Ok thanks. Yes closer is better obviously. I need to have a look at this because glass is reflective and will not let all of the radiant intensity of the light through it. The attenuation needs to be calculated. Thanks Adam
  14. Arouse1973

    Sealed Lead Acid Batteries

    It is best to connect the battery to the equipment and not any load. After all the equipment is what the battery is supposed to be running. Adam
  15. Arouse1973

    Sealed Lead Acid Batteries

    Absolutely, there are no rules that should be bent, batteries are dangerous, the small sealed batteries can explode if treated incorrectly. Car chargers are for car batteries, sealed battery chargers are for sealed batteries and gel battery chargers are for gel batteries. Some chargers say they...
  16. Arouse1973

    2 pole low frequency shelving filter design

    My pleasure Bob. So much nicer working with others on a thread than being on your own I find. Cheers Adam
  17. Arouse1973

    Sealed Lead Acid Batteries

    Hi Do not use a car battery charger to charge sealed Lead acid batteries. They can be damaged and potentially could explode. Either buy a correct charger for sealed batteries or use the equipment that the battery came from to do the charging. Thanks Adam
  18. Arouse1973

    Need help design UV Curing heads

    To work out the mW/sr of the UV device we first need to know the distance from the LED to the work piece. Any calculations you do will depend greatly on this distance so you must give this some thought first. Adam
  19. Arouse1973

    2 pole low frequency shelving filter design

    This is what happens without the capacitor. The gain which is 3.32 tries to amplify the input by this. But this would give you 5.27 Volts, it can't do that so the output goes as high as it can go with the supply it has. Adam
  20. Arouse1973

    2 pole low frequency shelving filter design

    Because the opamp will amplify D.C also it doesn't care if it's A.C or D.C. It will try and make the difference between the inputs approx. 0 V. So to do this the output will rise to a voltage that makes the non inverting terminal the same. But because you have a voltage divider the output will...
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