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  1. L

    Need help understanding importance of Inductance

    The following article, A TRANSIENT SUPPRESSION GUIDE, might help your understanding: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1338123/pdf/jeabehav00172-0065.pdf
  2. L

    Connection of Feedback and noise?

    Well, yeah, but how do you pick out just the noise from the signal at the correct phase in order to feed back the noise?
  3. L

    DC & Buzzer

    1. Have you ever examined how a buzzer is constructed? If your buzzer is covered, have you torn it apart to see what is there? Everyone should do that at least once. Inside you should see an electromagnet coil and switch contacts. Draw a schematic of the whole thing and tell us how you...
  4. L

    Need help with my final year project...

    My concern is with the component "U1". The original circuit shows two separate components, one IR LED and one phototransistor, whereas your circuit shows these as a single component U1 optocoupler. My question is how do you intend to attach U1 to a person's finger in order to sense the change...
  5. L

    Help me to make a 8bit to 16bit data forwarder type circuit..

    Take a look at the CD4067B 16-channel multiplexer/demultiplexer. The analog switches appear to be unbuffered so the switching is bidirectional with a channel resistance of 125 ohm in the ON state which is capable of switching CMOS-level logic signals. You would need 8 of these IC's, one for...
  6. L

    Impact sensor?

    What you need is a dynamic load cell. http://www.omega.com/pptst/dlc101.html Don't you normally find a leather pad on the head of a pool cue? Since leather is compressible it will absorb a lot of the impact force and change the peak value. So be sure to mount the impact sensor behind the...
  7. L

    Transistor/ current question

    From your description I don't believe that the 1.7A current was the problem. In both cases the base current from the microcontroller driving the transistor would have been the same, and the collector current would have been Hfe times the base current. The difference was the collector-emitter...
  8. L

    I have issues with MAKE: Electronics experiment 8? (The link may not work so tell me

    I can't tell for sure from the photo, but it appears that on the bottom the power is connected to the RED rail and the circuit is connected to the RED rail, while on the top the power is connected to the BLUE rail and the circuit is connected to the RED rail. If that is in fact the case then...
  9. L

    Schematic to reality conversion

    Solderless breadboard is the easiest to use but it is not a permanent solution. PCB is only for the professional or advanced hobbyist. I expect most people use solder on perf board. If you want to manufacture your own perf board from plywood or cardboard, I don't see any reason that it...
  10. L

    Schematic to reality conversion

    My favorite wiring technique is to use perforated Vectorboard with point-to-point soldered wires. See attached photos from a current project. For testing circuit ideas where only a few elements are involved, I tend to use solderless breadboard.
  11. L

    Whats the error in attached band pass filter?

    What does the Bode plot of that bandpass circuit look like? Can you post a picture?
  12. L

    I have issues with MAKE: Electronics experiment 8? (The link may not work so tell me

    The instructions for the experiment state, "...and then press the pushbutton very briefly. You should hear the relay make a buzzing sound." So did you hear the buzzing sound?
  13. L

    Op amp/Zener voltage clamper problem

    It appears there are two back-to-back diodes in series, so unless the opamp output exceeds 9 V there is nothing reaching the circuit output terminal except leakage from the '-' input terminal. Try disconnecting the diode from the opamp output and see if there is any variation in the 0.27 V.
  14. L

    I have issues with MAKE: Electronics experiment 8? (The link may not work so tell me

    Just what is it that doesn't work. The relay is wired as a vibrator; when you press the switch it is supposed to vibrate. Does it not vibrate? Can you not find the switch? Do the LED's not light up? Did it work before you added the capacitor? How about if you removed the LED's, the...
  15. L

    2 into 3

    This is simple. Just cut off the 2-prong plug and replace it with a 3-prong plug. If the 2-prong plug is polarized, then be sure to reconnect the two wires in the same fashion. Presto! You now have a 3-prong cord. If the amplifier has a metal case (or the power transformer has a metal case)...
  16. L

    Why wont this circuit work?

    Your design has elements of both bridged and paralleled amplifiers. See the following article for some hints on what you need to do to make it work. http://en.wikipedia.org/wiki/Bridged_and_paralleled_amplifiers
  17. L

    Regarding Depth Calculation

    Non-uniform sampling times are just another potential source of error that must be dealt with, along with sensor error and instrumentation offsets. You would need to manage the error budget carefully, since performing a double integration can magnify small errors into much larger error.
  18. L

    Regarding Depth Calculation

    The basic formula given is for a constant acceleration, and the "t" is for the duration of the acceleration. However, your package is unlikely to be subject to constant acceleration during its movement. In that case you need to integrate the A(t) function over the total duration with respect...
  19. L

    Break beam technogly

    On question #3: The upper limit on pellet velocity is about 1000 ft/sec, whereas the thickness of the light beam is probably around 1 mm. Velocity = 1000 x 12 x 25.4 mm/sec, so the time it takes the pellet to move across the beam is 1/(304,800) = 3.2 microseconds. Any PIN photodiode should...
  20. L

    Looking for a way to get 16 LEDs to flicker at "random" in a circuit

    Driving 64 LED's each in a random fashion is certainly doable but could require a lot of circuitry (64x1 LED circuit). However it could be possible to generate just a few random streams, and with time shifting and spatial diversity make it seem that all 64 LED's are driven randomly. What I...
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