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  1. Arouse1973

    Why are motors so expensive?

    Why don't you try your local model shop. Thanks Adam
  2. Arouse1973

    Large capacitor for power outages?

    I doubt it, 2.5F super cap (2*5F 2.7V in series + free demo PCB if you blagg it = 5.92 GBP. A surge protector on its own wont hold the supply up. Can you send me the link for the UPS unit for less than 10 USD that you have seen. :) Thanks Adam
  3. Arouse1973

    Wal Lenk soldering iron tips

    Yeah sorry I thought the LP25PT was another type of soldering iron, like the L25K. Thanks Adam
  4. Arouse1973

    dc to dc boost converter

    And here it is. http://www.amazon.com/RioRand-LM2596-Converter-Module-1-23V-30V/dp/B008BHAOQO
  5. Arouse1973

    Happy new year everybody.

    And you Dave. Thanks Adam
  6. Arouse1973

    Happy new year everybody.

    Happy New Year Happy New Year to you all. I have only been on here a short time and must say how friendly people are. It is difficult fitting in somewhere new when you have some expertise in areas that might conflict with others. But its been ok. Oh ok my 555 timer post might have upset a few...
  7. Arouse1973

    Wal Lenk soldering iron tips

    I can only see that the L25PT tip is replaceable. Thanks Adam
  8. Arouse1973

    A/B USB switch box noise

    Try connecting everything you are using to one mains extension lead. Even if it means moving the equipment into one room. Tell me that helps. Adam
  9. Arouse1973

    A/B USB switch box noise

    Yes Steve I think your right sounds like it might be a ground loop problem to me. Thanks Adam
  10. Arouse1973

    shielded cable helpful here?

    If it is 400Hz then a ferrite bead won't do the job, they are for higher frequencies. Are you able to measure the noise on a scope and tell us what frequency it is. Thanks Adam
  11. Arouse1973

    shielded cable helpful here?

    I agree with Dave, ferrite beads in the wires. But make sure they have the correct current rating, otherwise they will be useless. Try a small capacitor after the ferrite connected to 0volts this will form a low pass filter and which will attenuate high frequencies better than just a ferrite on...
  12. Arouse1973

    Isolated sense of AC mains (240V) voltage and phase

    I think you will find the voltage in lt spice is + and - of your value, so 50mV sine wave is 50 mv up and 50mv down 100mv peak to peak Thanks Adam
  13. Arouse1973

    shielded cable helpful here?

    You were told what was magnetic interference? If you unplug your headset then it will go away, you won't hear anything. What do you mean the noise has been around for years. Thanks Adam
  14. Arouse1973

    shielded cable helpful here?

    Shielded cable will only help if the noise is air bourne. If its in the cable it will only stop the cable radiating not solving the problem. Shielded cable is only really effective with a 360 degrees seal. The old fashioned pig tail is rubbish at this an is only any good at at a few Mhz. Thanks Adam
  15. Arouse1973

    Large capacitor for power outages?

    Fair comment but what you have to remember is that people posting on this forum might want to try somthing themselves rather than just buying something. Thanks Adam
  16. Arouse1973

    shielded cable helpful here?

    Hello I don't quite understand what your trying to do, can you explain a bit more. What is the cable doing, why HDMI?. Just bog standard twisted pair cable is quite good at reducing CM noise, that is if it is CM noise. Is the cable transferring data or power. Thanks Adam
  17. Arouse1973

    Circuit to activate the uC interrupt

    No probs Steve. One other thing to mention is that the output stage of most comparrators are open drivers. They will need a pull up resistor unless you use one with push pull output. Thanks Adam
  18. Arouse1973

    Large capacitor for power outages?

    Good idea Steve. Yes a battery and an ideal diode is your best bet. I must of had capacitors on the brain for not to think of that one. Adam
  19. Arouse1973

    Circuit to activate the uC interrupt

    Hi Steve 4.7nF is way too low, with say 50mV of noise coming in this will only reduce to about 48mV. You will need something like 1uF to give you about 3mV. But this still could trigger the circuit. Why not try a capacitor across the inputs so both inputs will see the same signal. I do this as...
  20. Arouse1973

    how to design butterworth IIR filter

    Is this a homework question. If so there is a section for this. if not then can you supply the missing data you say you have? 1) cutoff frequency 2)stop band frequency 3)Ripple in pass band 4)Filter order 5)Input voltages and impedance. 6)Output impedance Do you want the filter to...
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