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  1. Arouse1973

    Anyone made a sound card oscilloscope?

    Oh god, what am I thinking, why on earth did I think capacitor in series add....yes sorry Chris. :oops: Better get my electronics for dummies book out. Adam
  2. Arouse1973

    Pulse transformer

    I only wear that outfit on Sundays :) Adam
  3. Arouse1973

    Pulse transformer

    At last I have found a use for the 555 timer :D
  4. Arouse1973

    Anyone made a sound card oscilloscope?

    One thing you could try is to put a large capacitor in series with the input signal of the circuit before the diodes. I would start with 4700 uF 16V and see if that improves matters. The reason this is happening is the RC time constant of the input to the sound card is too short for such a low...
  5. Arouse1973

    Sensing circuit for line following robot

    Increase the value of R2, 470K. You still haven't told us what devices you are using. How far apart are the TX and RX devices? Adam
  6. Arouse1973

    measuring 3 phase circuits correctly

    Is your multi-meter a true RMS type? Your meter could be trying to resolve a sine wave with harmonic content. You will get strange readings if the meter is just the type that only passes the positive half of the sine-wave and then computes the bottom half as it expect this to be a pure sine...
  7. Arouse1973

    Anyone made a sound card oscilloscope?

    Being the input to a sound card doesn't the input have to be A.C? Not sure if you can measure D.C. Looks like the signal is going through the input capacitor on the sound card. just a thought Adam
  8. Arouse1973

    Which LED is going to work?

    Is this a quiz :)
  9. Arouse1973

    Item Identification

    Yeah he's always doing that, even when he's not very well :)
  10. Arouse1973

    Power supply return path question

    This is how I would do it for a single sided PCB. You could easily machine this on a PCB milling machine. I would normally use more than one layer if I was doing it for my work but it gives you an idea of the kind of layout that should work. Adam
  11. Arouse1973

    Power supply return path question

    What are you interested in? EMC related problems or operability. Signal integrity in many cases is a design specific environment, and it's down to you to decide if it's acceptable. Radiated, conducted emissions and immunity is a requirement by certain standards to be below a certain level...
  12. Arouse1973

    Help identifying this device and tips to hook it back up

    That's a bit of a beast..... +5 V @ 30 Amps.....nice. Hope it still works. Adam
  13. Arouse1973

    Sensing circuit for line following robot

    You are using an op-amp as a comparator which is something I try to discourage. But you have designed it now, and I think R2 is too high, you are using a photodiode which won't have a huge amount of current gain versus irradiance. Can you tell us what IR devices you are using. Edit R2 is too...
  14. Arouse1973

    Sensing circuit for line following robot

    Show us a circuit diagram.
  15. Arouse1973

    What diode is used in this schematic?

    Here is the formula if interested External traces: I = 0.048 x dT^0.44 x A^0.725 A = cross-sectional area in mils^2 dT = temperature rise above ambient in degrees centigrade I = current in Amps Adam
  16. Arouse1973

    What diode is used in this schematic?

    Dependant on the acceptable temperature rise and voltage drop you may have to increase the width of the trace. I am assuming your using 35 um base copper with no plating? With a 25.4 mm trace length on an external layer, 3 Amps will raise the temperature of the trace by about 8.5 degrees C, with...
  17. Arouse1973

    What diode is used in this schematic?

    Sorry just noticed it 1.6 mm Adam
  18. Arouse1973

    What diode is used in this schematic?

    Hi Kenneth Looking good, one comment is the 10K pull down will still give you 6 Volts on the sense input. Try a 5K6, this should give you 4.3 Volts. What track widths are you using? Adam
  19. Arouse1973

    Electric Calculations

    You have a couple of options. 1) Use a single resistor for each LED. You need to check what the forward voltage is at 120 mA if it's on the datasheet. So we will say it's 3.6 Volts for the minute. So (5 Volts - 3.6 Volts) / 120 mA = 11.6R (Use 12R) wattage is I^2*R = (0.12^2)*12 = 172.8 mW so...
  20. Arouse1973

    Electric Calculations

    Ah the reason I asked is because you said AC which makes a difference. Now we know it's DC then that's easier. Adam
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