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  1. Arouse1973

    What am I not getting about LED's

    The battery might be able to supply 85mA but what voltage does it drop to when doing this. If drawing 20mA drops the voltage of the battery to below what is required to run both LEDs then this could be the issue. Would explain why the LEDs didn't blow up when you tried it without any resistance...
  2. Arouse1973

    555's are terrible, no they're not, yes they are, no they're not

    I agree with this Steve. Merry xmas Adam
  3. Arouse1973

    Troubleshooting a power supply circuit - am I on the right track?

    Measure across the base emitter junction of the trannys, that might give us a clue. Adam
  4. Arouse1973

    Troubleshooting a power supply circuit - am I on the right track?

    Sorry dave missed that one. Cheers adam
  5. Arouse1973

    555's are terrible, no they're not, yes they are, no they're not

    Yes agree times have changed. But some people can't manage change. Merry xmas Bob
  6. Arouse1973

    555's are terrible, no they're not, yes they are, no they're not

    Thankyou some support at last :)
  7. Arouse1973

    Troubleshooting a power supply circuit - am I on the right track?

    maybe they are using the transistor as a power switch. Just because the device is rated at 1.5Amps doesn't mean they are using the available current. I would use one for as small as a few mA, they have much better noise performance than a switcher and at low current are quite efficient. And they...
  8. Arouse1973

    Troubleshooting a power supply circuit - am I on the right track?

    LM7810 is a standard regulator. Thanks Adam
  9. Arouse1973

    Troubleshooting a power supply circuit - am I on the right track?

    Dave why would you bypass a 1.5A reg with a 200mA transistor? Maybe I am being a bit thick here. Thanks Adam
  10. Arouse1973

    Reducing the Voltage to a square root of itself

    Oh and if you want a logarithmic response the replace the FET with a NPN BJT. Handy for amplifying small signal and attenuating large signal. Thanks Adam
  11. Arouse1973

    Reducing the Voltage to a square root of itself

    Sorry it is possible. Square root circuits have been around longer than micros. All you need is an op-amp an n-channel FET put in the feed back loop of the op-amp. Set up the amp as an inverting amp and connect the gate to 0V the source connects to the output and the drain to the inverting...
  12. Arouse1973

    Xmas Puzzle

    Hi Guys thought you might like to have a go at a puzzle. Take a 1V battery (Theoretical) and add two series resistor from + to - first resistor 100R and second resistor 900R. The point where they join we will call point A and where the 900R connects back to the battery - we will call point B...
  13. Arouse1973

    555's are terrible, no they're not, yes they are, no they're not

    Merry Christmas Dave:)
  14. Arouse1973

    Connecting monitor speakers to home stereo

    Ah this is a powered sub so you should just be able to plug this in and it should have all you need. Unless the amp has othe r than a headphone out you would need an amlified speaker set to hear it. If you have a home stereo with aux in you could use this. Otherwise you will need some sort of...
  15. Arouse1973

    Rechargeable LED Flashlight Help

    A switch, batttery +charging socket and the correct battery charger plus an led and resistor. Don't forget the batteries Thanks Adam. If you could give more detail then I could help further. How bright do you want it. How long do you want it to last before recharging the battery What size...
  16. Arouse1973

    Connecting monitor speakers to home stereo

    Looks like the only ouput you have is the headphone socket. You would need to connect this to an amplfier to hear it properly. Sounds like you want some sort of surround sound system. I don't think you will get the desired sound you require. Subwoofers are bass speakers and you would need some...
  17. Arouse1973

    Building a device from a schematic (Yet another work in progress)

    Very good article Steve. As you could expect can I make a few comments. You don't seem to mention anything about supply support or decoupling. Each IC in a design should have a minimum of a ceramic 1n to 100n across the supply and at least either a 2.2u tant, electrolytic or MLCC also. I would...
  18. Arouse1973

    555's are terrible, no they're not, yes they are, no they're not

    For hobbies fine Steve, but in my opinion they shouldn't be used for production designs they can create more problems than it's worth. Please read extract from EDN. My apologies Chris, for not realizing there are other people in the world that think analog is fun. I will have to pass on doing a...
  19. Arouse1973

    Merry Christmas everyone !

    And to you. Regards Adam
  20. Arouse1973

    Auto amplifier diagnostics, output very low

    Why do you say that Steve. It could be anything surely. Regards Adam
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