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  1. Arouse1973

    Clean square waves using a 555 timer?

    Ok another test if you have time. Remove the 555 timer and where the output pin would have been take the scope calibration and connect it there. then measure again with the blue wire connected as it would have been in the circuit. Adam
  2. Arouse1973

    LED strips help required

    Is this the sort of thing you were after? Adam
  3. Arouse1973

    LED strips help required

    You will most likely need a PWM circuit to do this. There are other ways but they are not so efficient. Adam
  4. Arouse1973

    LED strips help required

    Hello Do you want the lights to fad on and off also or just on and off quickly? Adam
  5. Arouse1973

    Hello :)

    Glad to have you here Conner. Welcome to E.P. Adam
  6. Arouse1973

    Hello all

    Hi Alex, welcome to E.P. Originally from Bracknell... now in Cornwall. Adam
  7. Arouse1973

    Clean square waves using a 555 timer?

    To rule out the scope probe could we try and measure the calibration output square wave of the oscilloscope? Using the blue wire in your picture which the scope probe is currently connected to. Remove it from the circuit and connect it to the calibration output of the scope. Adam
  8. Arouse1973

    Clean square waves using a 555 timer?

    Ok thought it might have been worth trying, thought it might have been a delay in the output of the driver stage. Interesting thought about reflections! However the reflection does seem rather high for a short length of wire and the scope probe is connected to the end which will make a...
  9. Arouse1973

    Ic of Common Emitter Amplifier

    Please show us your circuit diagram. Welcome to E.P BTW Adam
  10. Arouse1973

    Clean square waves using a 555 timer?

    That's great work, did you lower the frequency as I asked you to? Thanks Adam
  11. Arouse1973

    Clean square waves using a 555 timer?

    Just a thought, have you tried running the 555 timer at a lower frequency, say 1 KHz? Also how long is your ground lead on your scope probe, you haven't made it longer to connect to your PSU have you? Adam
  12. Arouse1973

    Clean square waves using a 555 timer?

    Please take some pictures of your circuit assembly. I would love to get to the bottom of this weird one. Cheers Adam
  13. Arouse1973

    Killing SSR (relays) - Need to understand

    This may also be of interest, might be worth taking a duff one apart? http://www.instructables.com/id/The-inner-workings-of-Counterfeit-FOTEK-SSRs/ Adam
  14. Arouse1973

    Killing SSR (relays) - Need to understand

    Data sheet for the SSR. http://www.fotek.com.hk/solid/SSR-1.htm Thanks Adam
  15. Arouse1973

    Solder mask or thru-hole mask in PADS Layout 9.5

    Great to hear you got it working John. Cornwall is a great place to live, better than Bracknell (near London) which is where I come from. Never seen the film so might look it up. Thanks Adam
  16. Arouse1973

    I am to design a switched mode psu without IC components.Help please

    Hello, no sorry I don't have any tutorials. I would recommend purchasing a book on SMPS design. Adam
  17. Arouse1973

    OPAMP as voltage comparator issue

    Ok no probs. Adam
  18. Arouse1973

    I am to design a switched mode psu without IC components.Help please

    Flyback convertors are a buck boost, do you need that? Also they have isolation from the transformer, I guess you will need this with your design. So you decide. If you don't need boost then go for a forward converter. Adam
  19. Arouse1973

    I am to design a switched mode psu without IC components.Help please

    Hello, The ESR of a capacitor will be in the data sheet for the capacitor you choose. A buck convertor is only regulated if it has feedback into the control circuit so the PWM can change to allow for different load currents. Adam
  20. Arouse1973

    OPAMP as voltage comparator issue

    Put a pull down resistor at the base of the BC548 down to 0 Volts. If you have another 68K try that, if that doesn't work you will have to lower the value of the pull down until the LED is off. It's always better to use a dedicated comparator to do this sort of thing. Although OPAMP will work...
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