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  1. K

    Boosting Regulator Current/ATX power supply

    Ante, it's not just the power that is of concern. You can't go below the rated beta of the transistor. This is normally associated with a base current that is too high compared to the collector current. This is because you don't have the VCE to increase the collector current beyond the base current.
  2. K

    transistor uses

    Does anybody follow the assertion that you can have a change in voltage divided by the change in current produce a change in voltage divided by a greater change in current. This is what a tranistor emitter follower does. But I'm looking for a three terminal device that will use use a common...
  3. K

    Boosting Regulator Current/ATX power supply

    What you have to do to make the circuit work is satisfy a couple of conditions. The output of 5v sets the load current. The VBE also sets the load current. They must work in conjunction. Now you have a VCE that is in question. Try adjusting your VBE down while maintaining 5v to the load. This...
  4. K

    Boosting Regulator Current/ATX power supply

    It's definitely a low beta. I have it. At the current you are using, the VCE should be greater. Get rid of the input resistor. You now have 7 volts VCE. Reduce your 3.3 ohm resistor to get a lower VBE. You now have what is called a limitation of the device. You may not be able to get the current...
  5. K

    Boosting Regulator Current/ATX power supply

    Thank you, I appreciate it because I am not good with devices. Your beta is low and you want to keep the VBE. so you need the correct VCE. By the way, if it's a 5volt regulator, then are you using the 5 volts applied to the 6volt ligt bulb. This is Ok
  6. K

    Boosting Regulator Current/ATX power supply

    It sounds like you have a low beta problem. How do you expect to use 12V input with a 12V regulator? You probably need 14V on the input. If the regulator isn't working right then it won't work.
  7. K

    Boosting Regulator Current/ATX power supply

    If the 7805 is similar to a regular type regulator, then it doesn't. Line regulation is the property where a changing input voltage causes the regulator to not regulate as well.
  8. K

    Boosting Regulator Current/ATX power supply

    Thank you Ante. I can see that the regulators current produces a VBE. The resistor then allows you to set the current by providing VBE. Isn't it interesting how this configuration for the transistor is not the standard seen in power supplies. My guess is that the regulator has the standard...
  9. K

    How to increase reactance in a coil of few turns?

    I have since found out that the current capability of wire is higher than the chart shows. I applied about 2A to 22AWG and the wire remained intact. I rectified mains and used some power resistors to find this out. I am not sure how high the current for 22AWG is.
  10. K

    Pulse Width Modulation

    Why is PWM so popular in motor control. I know why it is used, but what happened to the AC motor or any type of other variable waveforms that can be applied to motors. What about varying the voltage? How about varying the frequency instead of the pulse width. Can't you realize different motor...
  11. K

    Bench Test Equipment

    I found an oscilloscope on Ebay. It's a Madell 10 Mhz brand new. I am waiting for it to arrive. Does anybody know these oscilloscopes.
  12. K

    Many supply voltages

    I don't know yet exactly how much current I will need. But the voltages will be made up as I have gotten away from the standard voltaged and am looking to maximize so that I can include the right resistors. This is an extrodinary task. Why don't you think zeners are a way to go? I guess I must...
  13. K

    A new Ideas?

    Keeping it simple is the phrase that sticks out here. Many times the technology has come to a point that exceeds the ability of the novice to configure it to his liking. The best way to go about a solution is to use the most primitive devices. You might be surprised that you can effectively...
  14. K

    Boosting Regulator Current/ATX power supply

    You are using the tranistor backwards. The voltage will not be divided with the 3.3ohm resistor. You are not getting any VBE to turn on the transistor. You do have VCE and you do have the 7805 in a good position. I would use the standard setup and your only problem will be the voltage drop...
  15. K

    Pulse Width Modulation

    That is interesting. But where is the VDS you will need when the transistor is on. The motor will require 24V and you will be left without VDS. I should also note that mine too will have a low VCE at that current. So use a higher input voltage. This is the only way. I have it. You could operate...
  16. K

    Winding your own Transformer?

    I did some experimenting and found that 22AWG wire will hande an average a little higher than 1A. This makes me think that a high current transformer uses one magnet wire of a higher guage. Has anybody had this experience with current in a wire? I know that the peak current can be higher than...
  17. K

    OPAMP questions

    I have seen many configurations of the opamp and am still unconvinced of a few things. I believe it should be operated with differential inputs. I believe it should have the correct output bias current. Anything else is cheating the operation. It should also have the correct input bias current...
  18. K

    signal conversion

    A bandpass is not a low pass filter. The amplifier will turn the triangle shaped wave of the audio, of a single frequency, into a square wave. Then the pulses can be counted over a given duration set by the enable line. 5 pulses in .5s will give you a frequency. 6 pulses in a given .5s means the...
  19. K

    C problem

    I quiried another post to find out that many functions aren't supported by the WindowsOS. However, my compiler is compatible with earlier Windows versions. I guess I just needed to read my CD to find out. But I cannot believe that my functions don't work just because it's WindowsXP. I posted in...
  20. K

    Pulse Width Modulation

    At 24v you will get 11A. At a lower voltage you will get lower current. Since you are PWM the current will go from 11A down to something near 0A.
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