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  1. Arouse1973

    Horticultural led's

    Plants can also benefit from orange light. The orange light helps with chlorophyll b. http://www.ebay.co.uk/itm/like/221316894420?hlpht=true&ops=true&viphx=1&lpid=95&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=95 Thanks Adam
  2. Arouse1973

    Math question for a counting circuit

    You won't see 434Hz, the eyes can't pick this up. Think about 50Hz mains light bulbs and if you can see them flicker much. Adam
  3. Arouse1973

    Horticultural led's

    Check out CREE. They make some very bright LEDs. The brightest LEDs are the white ones which you don't want. But you could group the lower lumen colour LEDs together to increase the coverage. Adam
  4. Arouse1973

    Photodiode Circuit Help

    Yes correct this will still work without the 1K but the gain is reduced because the 1K lowers the feedback fraction which requires more output voltage to balance the inputs. The 0.1uF prevents oscillations due to input and output capacitance.
  5. Arouse1973

    Horticultural led's

    LEDs do vary their wavelength within each colour band so you may need to know the exact wavelength required. The exact power needed is difficult to work out because some plants require less light to grow. Having a quick look into it, plants need anywhere between 5800 and 46000 lumens per meter...
  6. Arouse1973

    Grounding Question

    That's a valid point Donkey, but doesn't make it right. For example I have a power supply on my desk which has a green connector a black connector and a red connector. The green connector is Ground and has a ground symbol. What do I call the black connector then? I can't call it Ground...
  7. Arouse1973

    Horticultural led's

    Red, Orange and Blue LEDs. Ratio 7:1:1 is sometimes used. Standard 5mm HI clear lens types. Adam
  8. Arouse1973

    Grounding Question

    I know most people use it but please try not to use the word ground for common. It is not the same. Also neither is negative appropriate. In doing so you will confuse yourself when you do come across both and think they are the same. The correct terminology as steve has said is conmon or zero...
  9. Arouse1973

    Science Competition Help

    If you want pwm. You need a triangle wave oscillator and a comparator with an adustable input using a pot. The pot picks up on a portion of the signal and as you vary the pot the pulse width changes. Adam
  10. Arouse1973

    Record from Webcan without Computer

    Yes I agree Dave. What about a tablet easier that computer.
  11. Arouse1973

    Help with Basic Programming

    You assume we know what an mq2 sensor is and a mega thingy me bob and a sainy thingy. Also what is 750, 750 what volts,mili volts, mA. Can you be a bit more specific please. Adam
  12. Arouse1973

    voltage and current source

    Just say thanks will do
  13. Arouse1973

    Newbie circuit modification

    Darlingtons have much higher gain, its not just about curernt handling. You may need to redude the base resistor and still keep the same transistor. The cuurent you need divide by the hfe of the transistor is the base current you need. Then just check the transistor you have can handle that base...
  14. Arouse1973

    building an audio crossover

    Your diagram is sallen key. You don't need to do anything just if your using single supply just follow my design.
  15. Arouse1973

    Very Simple LED Light Project

    Lol steve you keep selling that one, but it is rather good.:)
  16. Arouse1973

    building an audio crossover

    I would add another upper voice speaker as I think you have already mentioned. The cut-offs below are a good starting point which you can adjust for your preference. Bass 90-120Hz Lower Voice 120Hz-500Hz Upper voice 600Hz-4Khz Tweeter 4Khz-8Khz As always the author doesn't show the...
  17. Arouse1973

    Help needed with a dark activated switch

    When you say with no load you get 5.2V. How are you measuring that.
  18. Arouse1973

    IR/UV Light

    Oh sorry didn't realise the reduction in UV lights. You have to calculate the resistor value for the current you require. IR = (9V-1.2V)/0.1=78R each. Resistor Power =I^2*R=0.78W UV =(9V-3.3)/0.02= 285R each or 250R if they run at 4V. Resistor Power =I^2*R= 0.114W Adam
  19. Arouse1973

    Potentiometer Resistance ?

    If you need a greater level of adjustment then I would go for this one. At half pot position you will have half the supply current of the max. Although the circuits maximum current will be reduced slightly because of the VE drop. Adam
  20. Arouse1973

    Electrolytic capacitor in timing use?

    C8 across Q5 is 10uF is it not?
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