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  1. K

    Integrated circuits

    Does anybody know about IC's. I've seen many electronics components, but haven't researched their designs. How complicated can they be?
  2. K

    Amplifier feedback

    Does amplifier feedback create more stability because of the DC biasing? There is nothing to combining the input with output.
  3. K

    Final stage amplifier

    Why do final stage amplifers tend to use discrete transistors? If the previous stage is an integrated IC, why can't the last stage be?
  4. K

    Transistor base current

    How much change in transistor current should there be for best signal quality? I'm using a 741 opamp input 100mVpp. I think it's DC biased at 100nA. Should I use a smaller input signal or is 100mVpp a good size?
  5. K

    AC power outlet

    Does anybody have an explaination as to why the 5th harmonic in the 120Vac 60 Hz home outlet is so high? And is a battery voltage supply better than a conventional AC to DC power supply?
  6. K

    Active filters

    Some active filters are designed at resonance and some are not. It would seem that resonace would cause more problems in circuits. Doesn't a high pass filter followed by a low pass filter and an amplifier produce the same result without the added harmonics?
  7. K

    resonant filtering

    Are power supplies designed at resonant frequency? I've used many that weren't and I've never seen the circuits that show it.
  8. K

    circuit distortion

    IC devices have a low amount of noise according to data sheets. But is it a good indicator of signal distortion? Transfer characteristics show to be different depending on the transistor. So does this mean that transfer charateristics are negligible, even though they do operate on small areas of...
  9. K

    Multiple base/emitter transistors

    A biploar transistor OR gate uses an input transistor with two emiiters. I have never seen these used elsewhere and am surprised to see it used for OR gate design. Are unusual devices not seen so much because of cost, availability, or design difficulty?
  10. K

    powering on and off

    When building a circuit from initial design, a lot of components fail prematurely. Is it due to electrically stressing the components temporarily, or powering the circuit on and off? Most commercially bought products are rigorously tested, but I have some simply designed circuits that would...
  11. K

    MOSFET VGS

    MOSFETS tend to have a high VGS requirement. I see them used a lot in power supplies. But the real benefits in using a MOSFET over a biploar junction transistor, although not immediately noticeable from a schematic, don't appear to be utilized. Might it be better not to use MOSFETS at all? Or...
  12. K

    555 timer

    Simple circuits such as the 555 IC are still being used. Microprocessors use a variety of simple circuits so as not to introduce unnecessary problems. So why do so many electronics products have so many components?
  13. K

    transistor emmiter capacitors

    I've seen some circuits that use a capacitor in parallel with an emitter resistor. The RC time constant needs to be short compared to the period of the input, or signal distortion will occur. Is this a real consideration of circuit design, or does it not really matter in most circumstaces?
  14. K

    Re: Band Pass Filtering & Impedance Match

    An LC filter uses larger value components than what is concerned with impedance matching. It would be the main filtering section and the impedance matching done to help eliminate problems caused by a transmission line or requirements of the devices connected to it.
  15. K

    current and voltage out of phase

    Does current that is out of phase with voltage mean lower available power. I see inductors used everywhere in power supplies, but are they used for more than ripple reduction?
  16. K

    Free wheel rectifier

    I did a little calculation with turning on and off a relay. It doesn't seem like it would always be necessary to add the reverse bias diode. I've seen it used many times, but isn't it just a small precaution? It looks like most of the energy is just burnt up within the coil, and you shouldn't...
  17. K

    Automobile ignition power transistor

    Has anbody ever heard of these going bad? I want to replace mine, but it's too expensive. I just want to know if I might get better performance with a brand new ignition power transistor?
  18. K

    AC solenoids

    Why doesn't AC make an AC solenoid move in and out? Also, what is the real benefit to using AC as opposed to DC? And, if I put a strong magnet next to an inductor, how does it affect the way that inductor works in the circuit?
  19. 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...
  20. 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...
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