Search results

  1. K

    filtering

    From what I gather, resonance allows for only about 65db/decade filtering. Is it okay to operate an LC away from resonance? Less filtering means less loss if you aim to conserve your bandwidth.
  2. K

    transmission lines

    Corroboration on a few things would be appreciated. A transmission line can appear to the source as a parallel resonant circuit, a series resonant circuit, a capacitor, or an inductor. When constructed correctly, the source only sees a very high resistive impedance.
  3. K

    spectrum analyzers

    I wanted to make a high frequency dual slope A/D one time. I found the counters available were a little slow. Does event capture on an analyzer make use of an A/D? If so, how is it done?
  4. K

    BJT biasing

    Does low current biasing have more to do with transistor longevity? I don't think so, because I have seen transistors biased at low current but a high VCE. I plotted beta one time, and I think it goes like this : Increase the current from zero and the beta goes high, very high. Approach about...
  5. K

    series RC circuit

    Anybody ever notice that if you apply, let's say a triangle, to a series RC circuit, the rate of change of voltage on one side of the capacitor is different from the rate of change of voltage on other side because of reduced amplitude? Even phase shift can't correct this. This means the...
  6. K

    opamp phase compensation

    Does the phase comp. capacitor placed at the input reduce the capacitance because it's in series with the BC capacitance of the opamp transistors? The opamp in general kind of bewilders me because of the feedback resistors dictating exact gain and handling all the current. So I would not be...
  7. K

    Feats of engineering?

    I ran the same low frequency square wave into a two input gate expecting complete cancellation on the output. However, the latch I had on the output would always set. It appears there was enough offset through the gate to cause a pulse. Does that sound like the problem?
  8. K

    High frequency A/D

    How do you digitize high frequency? I was going to use a counter based A/D, but the counters available are too slow.
  9. K

    Very long RC time contant!

    The RC time constant must be long enough with repect to the signal time to cleanly pass the signal through the capacitor. Is this statement true or false? Answer : True. I wanted to revisit this topic because I was sharply denounced last time. Now, I know the truth. Any takers?
  10. K

    low current transistor bias

    I have this schematic with unknown bipolars. The transistors are biased at an extremely low current and higher voltage. Without the ability to have a large change in collector current, as it's biased at like 1mA, the input signal and output signal are destined to be small. Even the final amps...
  11. K

    The right tool

    Why are people designing electronics at the fringe. They use a 10 amp supply for a 10mA application. If the chip says 0 to 18 volts, they use 2. They use a 10MHz scope to measure 10MHz. They use complicated testing devices, but aren't completely sure of what they are measuring.
  12. K

    Stupid observation

    My wrist strap has a current limiting resistor for my protection. This won't help one iota if a touch high voltage. Is this about freedom from liability?
  13. K

    RLC phase relative to source

    Ever plotted phase shift? I created a peak to peak voltage divider with a series RC. I set the input to be a triangle and the phase shift to be 45 degrees. I happened to notice that all three voltages had to be in phase at peak source voltage. So I am thinking that phase shift occurs on the...
  14. K

    Voltage

    We are accustomed to maintaining differences of potential in electronics. But isn't the voltage level, of let's say a rock of copper, an absolute. I believe that in theory, you could just use one probe to measure voltage. Never seen a voltage meter with one probe, but there could be one, since...
  15. K

    voltage regulators

    I was working with independent power souces when I discovered that the book example of a voltage regulator falls short. It appears that a single pass transistor is not adequate if the regulator is to sink current. You must have a complementary transistor. Can anyone corroborate this?
  16. K

    phase shift and feedback

    The way I understand it, phase shift is detrimental to the effects of feedback. We know that the phase shift caused by a transistor of 180 degrees is different from the phase shifts caused by reactive components. In fact, while the transistor phase shift produces an exact replica of the input...
  17. K

    test equipment bandwidth

    Does anybody know why they can claim good accuracy with equipment at all frequencies extending down to 0 hz. From what I have seen, the more you pay the higher the frequency that can measured. Now, does that mean you are paying for the extra circuits that are put into the equipment so that you...
  18. K

    p type and n type

    I think that sometimes authors are confused about how to explain electrons and holes. I have read that holes don't move, and I have read that holes are pushed into the n type material. I think it is easier to explain from the viewpoint of atomic structure. P type material is made such that there...
  19. K

    Digital mishaps

    I am curious when it comes to digital communication errors. We know that that there are error detection schemes in use to help catch these errors. We also know that these errors occur in products that have been fully tested and have no hardware problems. One question I have is why are these...
  20. K

    opamp won't output zero

    I did this experiment with an opamp and found that the output had quite a bit of DC offset. It looked as though the difference between the inputs was being gained too much. And yet I was able to get a reasonable sized amplification. So if it's gain, which I think it isn't, why is it still high...
Top