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  1. K

    State Variable active filter

    High input impedance, high gain, differential input. This is what separates the opamp circuit from the discrete components. Why use the opamp if you don't need to utilize one of these characteristics?
  2. K

    Amplifier circuits

    Does anybody happen to notice the wide array of amplifier circuits available. I am tempted by the IC selections but am wary of the configuration data. I don't like the idea of a circuit where the external components aren't dictated. I want to know what the components are doing and how this...
  3. K

    State Variable active filter

    An opamp is the amplifier of choice because it satisfies a few main requirements associated with electronics signal handling in general. Stability is normally dealt with as a result of the high frequency. The reactive components work better with discrete transistors.
  4. K

    State Variable active filter

    There is a simpler solution than the opamp. This sounds like a transistor capacitor transistor capacitor solution. Actually, I believe the filter should be of the inductor capacitor type. This way you can get rid of the resistors. Just remember that it is harder to measure the voltages with...
  5. K

    series RL

    I let the resistor be a higher value so that Vs is in phase with Vr. This allows me to calculate Vl rather than measure it. Vl is 90 degrees out of phase and it throws off the measurement such that the voltage doesn't add up. Does anybody have experience with this? I think the voltage can be...
  6. K

    regulators

    Do you notice that the control element is sometimes an opamp. Iwould tend to use a base transistor with an exterior, digitally controlled analog IC that feeds it. I am sure the IC would probably have an opamp.
  7. K

    State Variable active filter

    A roll-off of 40db can be stable. This will occur at a higher frequency. A capacitor affects the phase margin. The capacitor is also a gain element. A state variable device is just a filter with gain. Try not to confuse the 40db of the opamp with the 40db realized from the state variable filter.
  8. K

    author of the transformer article

    I was able to construct the autotransformer with a couple of drawbacks. It turns out that I had to solder the magnet wire together and tapping it is difficult when it is already wound. I was aso too lazy to make the wire large enough to handle the current. We will see if this is the case.
  9. K

    regulators

    It also occured to me that the regulator is regulating against the changing signal. Is it safe to say the regulator is a junction of two signals?
  10. K

    Capacitor variety

    I am in the process of making my own inductor. I used a transformer core and wound it using magnet wire. One can only speculate as to the equation of homemade devices such as these. Can you really expect a very simple homemade capacitor to obey a simple equation.
  11. K

    transistors

    I am trying to bias a pushpull amplifier on paper. The two collectors are connected together and the emitters go to the power supply. The gain is subjective and I feel like it is best done with the circuit built. Does anybody know how accurate the PN junction is? You can't even get the current...
  12. K

    transformer core

    I have found a transformer core to make my own transformer. The magnet wire is very thin and difficult to deal with. Magnet wire is also difficult to solder with. It is too bad that the core can not be sawed apart to create a bar like core. A steel bar would make this much easier.
  13. K

    regulators

    What is nice is that since the control is already digital, a digital device can be used to help regulate logically. Maybe there can be compensation for voltage drift. The problem is the regulator can't regulate the output of a filter capacitor. So I guess that a power supply filter might have a...
  14. K

    regulators

    I am concerned with linear regulators and switching regulators. It occured to me that the switching regulator has a filtered output. I believe that a regulator should regulate and not filter. Does anybody have experience with power supply regulators?
  15. K

    transistor voltages

    I am using a 3amp bipolar transistor. My power supply won't handle the 1.5 A that I need. Does anybody want to guess as to the voltage I should use to bias this.
  16. K

    Capacitance meter

    I know there are specific designs for a capacitance meter. I wonder if designing your own will work too. Sometimes starting from scratch will give you a simple design that does work.
  17. K

    5 volt regulated power supply HELP!!!!

    I can see your regulator is missing feedback. A constant voltage doesn't regulate against the changing PN voltage.
  18. K

    Capacitor variety

    Actually my meter is fine. I just did not know that it would not measure an AC voltage when there is offset.
  19. K

    Capacitor variety

    Does anybody notice the variety of capacitor types that exist. I am sure there is a measurable difference, but it is subtle. Of course the value of the capacitors are different, given the same construction. My problem is my meter. It' doesn't measure low voltage AC very well. It's a radio shack...
  20. K

    5 volt regulated power supply HELP!!!!

    I am thinking about a power supply too. What I would use is a large inductor and a large capacitor. Remember that the amplitude of the ripple changes as the load changes when you look at it from an RLC respective.
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