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  1. (*steve*)

    Design of a transistor curve tracer

    Why not find something more modern as a replacement. The datasheet does have the typical curves, but nothing out of the ordinary. Now, I'm not sure. Are you talking about what you're using in your circuit, or the devices you're drawing curves for?
  2. (*steve*)

    Design of a transistor curve tracer

    Positive feedback works differently to negative feedback. Whereas negative feedback tends to reduce the output swing of a op-amp, positive feedback increases it. So, if, with negative feedback, the voltages on the inverting and non-inverting terminals differ, a change in the output brings them...
  3. (*steve*)

    Time reversal transformation

    I think the problem is, for the equations Sin(a + x) = f( sin(-x) ) Cos(a + x) = f( cos(-x) ) Find a and f() such that 0 <= a <= 2π and f() can be implemented as an electronic circuit. I think I have done half the work by laying out the equations. There problem is more of a test of...
  4. (*steve*)

    Design of a transistor curve tracer

    I've honestly never tried to do this. I normally just post the thumbnail of the images with interspersed text leaving it up to the reader to get the full image if they're interested. As someone who tends to read this site on a phone more often than on a PC, text next to the images would...
  5. (*steve*)

    Design of a transistor curve tracer

    It depends. The input signal can also cause the output to alternate from one supply rail to the other.
  6. (*steve*)

    Design of a transistor curve tracer

    Applying net positive feedback does not result in a smaller output voltage. It will result in the output being at one supply rail or the other (or however close to them the op amp can swing them).
  7. (*steve*)

    Time reversal transformation

    I expect it is.
  8. (*steve*)

    Time reversal transformation

    A piece of wire will so it for a time delay = pi/ω for sin and 0 for cos. They are periodic waveforms, so a delay of the appropriate length (essentially aaphase change) wil result in exactly the same as -ωt. Now, if you want both functions to be reversed and delayed the same amount... You'll...
  9. (*steve*)

    need component detail

    It may be a 68μF capacitor.
  10. (*steve*)

    Pulse dropping circuit.

    So if you got a series of 10 pulses, you'd want to suppress the first, fourth, seventh and tenth? Is additional power allowed? Do the pulses have a consistent voltage? Do the pulses have fast rising and falling edges? Edit: I'm thinking that a circuit employing a 4017 and an AND gate might...
  11. (*steve*)

    Time reversal transformation

    How about a piece of wire? A sine wave in reverse is a sine wave.
  12. (*steve*)

    What value is this SMD yellow Tantalum capacitor?

    It's likely that you'll see the same capacitance both ways. BTW, I was suggesting you do a diode check, but it appears these are capacitors. The diode check needs to be done both ways and you look for 0.7 (approx) in one direction and something much larger in the other.
  13. (*steve*)

    Resistor Value.

    Yep, that sounds fine That's a bit higher than I would have expected, but probably fine. No, I think it's due to the low ESR capacitors that will look like an almost short circuit when discharged. That reverse biased diode prevents a reverse polarity voltage appearing across the power...
  14. (*steve*)

    What value is this SMD yellow Tantalum capacitor?

    In that case they're probably capacitors. capacitors also often have one end marked with a white stripe.
  15. (*steve*)

    What value is this SMD yellow Tantalum capacitor?

    I would test them using the diode test function of my multimeter first. Looking at your better image, it's possible they are not diodes.
  16. (*steve*)

    What value is this SMD yellow Tantalum capacitor?

    That looks like 47μF 10V. It should read as 47μF. The black devices are diodes.
  17. (*steve*)

    Casio WK3800 keyboard won't switch on

    My first guess is that it's a power supply problem. I don't suppose you have any experience in electronic repair do you?
  18. (*steve*)

    6 Sided RGB LED Alternating Moodlight

    The various arduino drivers for these LED strips come with sample code that may do pretty much what you want. I'd start from one of these examples and then learn enough C++ to change the code to do what you want it to do.
  19. (*steve*)

    Single pulse output

    Be aware that your switch may bounce. If the duration of the required pulse is short, the switch bounce may cause multiple pulses to be generated. For longer pulse duration, the bouncing may elongate the pulse by the duration of the bouncing. One fix is to have a second monostable (with a...
  20. (*steve*)

    Design of a transistor curve tracer

    Hardly.
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