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  1. K

    RC phase shift

    Hey Kevin, If you have a non-linear load (i.e. a rectifier) harmonics are created. Harmonics are created by tuned ampflication. You may be tuned to let's say 350Hz, but you will have to change the outlet current quite a lot to see it materialize in the outlet waveform. My question is, where are...
  2. K

    RC phase shift

    Could it be that the noise found at the home outlet contains all sorts of things. They talk about all types of nonlinear loads putting harmonics into the power distribution system, but they only mention the 60Hz harmonics. I don't how I would go about creating harmonics from a "pure" 60Hz...
  3. K

    Gain control

    Using the noninverting input will help a lot. Use high value resistors to bias the opamp and about a 1uF coupling capacitor.
  4. K

    sinewave trouble

    I made a high pass RC followed by a low pass RC. The lowpass was of a higher impedance, so as not to affect the high pass. I set the fundamental around the knee of the filter curve for both stages. Wow, the sinewave from the transformer looked bad, and after the filter the sinewave looked great...
  5. K

    sinewave trouble

    And look at the graph, almost every single harmonic is 100db down from the fundamental. They almost don't even exist.
  6. K

    sinewave trouble

    Okay, I made the high pass RC, the capacitor the input. I kept the capacitor at .1 uF and the resistor 100 ohms. I used the outlet power stepped down by a transformer. Bingo, the 60Hz sinewave from the electric company was totally distorted by the RC. So your saying I get this totally distorted...
  7. K

    RC phase shift

    I think phase shift occurs on upswing and the downswing, not at the point the voltage changes direction. This is why there is no distortion. I have plotted this scenario with real numbers several times. If the input to an RC is 14vpp, and the resistance and reactance are equal, then each element...
  8. K

    sinewave trouble

    Very good. But I can manually ramp a voltage up and down like a triangle, and there will zero harmonics, and a corner which would have very weak power down to zero hertz.
  9. K

    RC phase shift

    When I plot phase shift on paper, I get inevitable distortion. I know the waveform looks reduced and undisturbed on the oscilloscope, as it should. Is there "less" to phase shift than what is normally described? Anybody reading about phase shift, who did not know otherwise, would say the...
  10. K

    sinewave trouble

    With a series RC circuit, you must be wary of the time constant, or you get major distortion. But you can't easily see the distortion with a sinewave. My 8038 has a triangle output, and it's buffered by an opamp, so it's not affected by the RC. I can see the time constant distortion with a...
  11. K

    110v supply

    Okay, but a copper wire does have a threshold current, doesn't it? If the wire doesn't blow with the current it has through it, it will never blow. You can't walk away from a wiring job, only to have the wire blow in a few hours.
  12. K

    110v supply

    Audioguru, you know the rate of change of voltage goes to zero at the peak of the input, it must in order to change direction. A 20A rms current rating sounds right, and I don't know the construction of a circuit breaker. But I thought that a regular piece of wire will break at a threshold...
  13. K

    110v supply

    I think a 20A circuit breaker is capable of more current. At the peak of 120vac, the reactance of the transformer is really low, only limited by resistance. I have always thought a fuse was rated for max. current, I know semiconductors like diodes have a surge current rating. I also know of slow...
  14. K

    110v supply

    I attempted to wrap bundled magnet wire around a transformer core one time. In theory, the inductance of paralled magnet wire would be low, and it was. So I had a low inductance, low resistance, high current wire. To develop high current, the inductive reactance should not be high anyway, am I...
  15. K

    Help me to understand the MC3359P IC

    I think in most cases, there is no intention to step down the frequency of an FM carrier. AM uses mixers. If you play with the frequency of FM, you might not be able to recover the message. It must be an AM IF receiver.
  16. K

    Help me to understand the MC3359P IC

    The 10.7 MHz is the carrier received from the antenna or cable, whichever. I believe the RSSI is a digital I/O of the microcontroller. They are always many I/O's, I think this is a popular one.
  17. K

    filtering

    Useful knowledge, I appreciate it. If your right!
  18. K

    filtering

    Yes, SAW filters look great. Many LC circuits don't involve resonance, but many do. I was suggesting the fact that a good signal filter can be made without using resonance. Is a nonresonant LC signal filter a stupid idea?
  19. K

    a high pass filter question

    I belive the component count should be higher too, because it takes more circuitry to go from airwaves to large signal on a low impedance.
  20. K

    a high pass filter question

    You will notice that a small radio doesn't produce much volume, and it's not because of the small speaker or the size of the battery.
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