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  1. Arouse1973

    Need Help Understanding Hi Current Add On For LM78XX

    Hi Rory This sounds like the common approach used to shunt current from the regulator to increase the total current that the circuit can supply. Your right with most of your assumptions but BQ1 I think is the gain of the transistor. I have added the picture to help others. If you work it out so...
  2. Arouse1973

    High Voltage component

    Agreed if a direct lightning strike hit the wires then game over. But this is not as common as you may think. The lightning stroke that hit's the ground generates a massive electric field which will induce currents into fence wires as they are basically long antennas. It is this that the...
  3. Arouse1973

    Assistance with Transistor Theory

    We all know how a transistor works, even if there is this current control versus voltage control debate. Lets put it to the test then. LVW can you show us the method you would use to design a transistor amplifier. Lets say operating from 15 Volts and a gain of 10 with an input of 100mV, we will...
  4. Arouse1973

    High Voltage component

    No, thats the whole point. Think about how they work. :)
  5. Arouse1973

    High Voltage component

    Could they be lightning suppressors? Adam
  6. Arouse1973

    What is a low input current line receiver

    Hello Line receivers will generally be used in differential signalling systems like RS485 for example. These use differential pairs to send data from one point to another. This is used to help prevent common mode noise from degrading systems performance. The opto isolator does two things, it...
  7. Arouse1973

    Thermistor Mounting Type

    Yep. Free hanging has a wire attached to the device. Through hole is soldered to a PCB directly. Adam
  8. Arouse1973

    Projects involving vintage CPUs

    So will you be smashing plates this Christmas? :) Ebay do some cheap brooms. Adam
  9. Arouse1973

    Merry Christmas to all!

    Merry Christmas every one. I would just like to say that my time on here has been great. I would like to say a big thanks to the moderators for their continued support, a big thanks to Kris. Amongst all the many experts on here I dont know if I have made an impression. I would like to think I...
  10. Arouse1973

    Cuk converter ripple current

    I struggle with maths myself. We were never told what any of it was used for so I didnt understand what use it had. l'll see if I cant put something together for you, but might be a few days as I have to do a bit of shopping. Adam
  11. Arouse1973

    2-10v or 4-20 dimming of 120v light bulb

    Yes I have been bitten many times :) But he does say 120V bulb in the title.
  12. Arouse1973

    2-10v or 4-20 dimming of 120v light bulb

    I think it's 120V Kris, I am guessing A.C. Adam
  13. Arouse1973

    2-10v or 4-20 dimming of 120v light bulb

    What about an automatic light dimmer using an LED and LDR. The light dimmer circuit is fairly simple so instead of using a POT which you turn to increase the brightness you control the current through the LED. So when the irradiance on the LDR increases as the LED gets brighter then this changes...
  14. Arouse1973

    Transistor base resistor calculation on 2N4401

    You divide your collector current by your gain. This is your base current. You then take you input voltage and subtract 0.6 and divide this by your base current to give you your base resistor value. Adam
  15. Arouse1973

    Buz103 replacement transistors

    Yes easy for some, but thats why they come here for help. And you are helping so good. Keep your head In those books, make me proud John :)
  16. Arouse1973

    Buz103 replacement transistors

    Well done John, good effort. Adam
  17. Arouse1973

    IR Transmitter and Receiver set

    Thats a bit of a lame description. Even with my crystal ball I dont know exactly what you want to do. Can you explain more? The more detail you give will depend on the level of answers you get. Adam
  18. Arouse1973

    Cuk converter ripple current

    What dont you understand David Adam
  19. Arouse1973

    Resistance of Primary Winding of a Transformer

    Right John you can work this out. Do an example, find a transformer or make it up, which you know the unloaded primary current. Then work out the inductance by using XL=2×pi×f×L. f being your mains frequency. XL being the AC resistance. Adam
  20. Arouse1973

    Resistance of Primary Winding of a Transformer

    Yes correct. Reactance is the reason for this and a small resistance also. Adam
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