Search results

Search Forums New Posts
  1. K

    design square waveform oscillator circuit/ relaxation oscillator

    I think a relaxation oscillator is a good job for an opamp. I prefer the opamp to always source up to about 20mA, as opposed to sink. The problem with opamp outputs is that they are prone to high voltage swings, which will destroy the transistor. I am not sure that propagating a square wave in...
  2. K

    The caps surrounding the LM7812 regulator?

    Do you suppose the circuit is designed with a load taken into account, or does an increased load just take away from the regulator?
  3. K

    The caps surrounding the LM7812 regulator?

    Sounds extraordinary, but the input to most regulators is a charged capacitor. All the regulator needs to do for the most part is not interfere with the capacitor voltage.
  4. K

    The caps surrounding the LM7812 regulator?

    Why must the gain be high within the regulator. If the load current brings the voltage down a volt, bringing it up a volt can't require too much gain, unless your reducing the feedback to the control element.
  5. K

    AC solenoids

    Okay. What I'm getting at with the strong magnet is this. If I use a coil to create an electromagnet, and the electromagnet is used to let's say pick up a block of steel, how does the load of steel affect the coil. It must drain energy from the coil. If I am draining energy from a coil, that is...
  6. K

    The caps surrounding the LM7812 regulator?

    I was also thinking that since the regulator current could be changing significantly, the phase could be changing, which would hinder the regulator's ability to regulate. A capacitor would then help the regulator to not be the cause of phase shift.
  7. K

    The caps surrounding the LM7812 regulator?

    The chip designers don't have any idea where the regulator is going to be used. The operating parameters are also wide. It's nice to know that the regulator can be enhanced by adding additional capacitors, but I wouldn't throw them in without knowing.
  8. 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?
  9. K

    5 volt to 3.3 volt

    I don't see what makes 4v to 7v zeners inherently better than the others. It may be that this particular manufacturer focuses on 4v to 7v zeners, letting the other ones they make just be as they are.
  10. K

    5 volt to 3.3 volt

    Increasing diode current increases diode heat and diode voltage. If I apply heat to the diode, I think the current will be higher, which means the voltage will be lower. Applying heat is different from dissipating heat. If I char a resistor with a heat gun, it doesn't mean I'll develop a lot of...
  11. K

    5 volt to 3.3 volt

    Nice circuit. How good do you think it regulates?
  12. K

    noisy power supply line

    Why are you loading the input to the amp? I had a cheap car radio, it had a constant buzz to it. I put a little more expensive radio in, it works great. I think your amplifier might be sensitive to a little supply noise, but a better amplifier wouldn't be. As far a fixing the problem, that cheap...
  13. K

    Project Motorola Hi-Fi Amplifier

    I have used two, parallel and opposite ,diodes on the opamp output to limit the output swing. An accidental high voltage swing can destroy the input to many devices.
  14. K

    5 volt to 3.3 volt

    I think a couple of diodes wouldn't be bad. You can convert logic levels if your stuck with a 3.3v logic device. Just power that device alone with a AA cell. But you have to watch your logic IC's when appending transistors and resistors. Often you have to source and sink within 10mA, or just...
  15. K

    RC phase shift

    No, but if the harmonics are of higher magnitude, filtering them out will reduce your composite significantly. It doesn't mean your fundamental is reduced, but the composite is reduced.
  16. K

    RC phase shift

    Okay I see, what I thought said voltage meant decibel. The harmonics don't even exist.
  17. K

    RC phase shift

    Go here www.smartdev.com/pdf/ac_power.pdf. The graph says the fifth harmonic is about half the voltage. Filtering out large magnitudes not only affects the waveforms appearance, it affects the amplitude. I see it very good when I apply superposition theorem.
  18. K

    RC phase shift

    The third harmonic from the electrical outlet is about 50% magnitude of the fundamental, the fifth is quite high too. If these harmonics were filterd out as soon as they are generated, then the amplitude at your outlet would be lower. Filtering out the harmonics once it comes from the outlet is...
  19. K

    RC phase shift

    Okay, now I'm reminded. The power line harmonics come from the alternators used by the electric company. I can't believe an alternator spinning out 60Hz can produce such strong odd harmonics. Maybe the higher harmonics are what we  really want, but we run 60Hz so that the alternators don't have...
  20. K

    RC phase shift

    I'm thinking crystals are the main ingredient for generating harmonics. Producing perfect multiples of a fundamental does not sound easy at all without a crystal.
Top