Bedini RPX Sideband Generator



Monero XMR

Page 7 of 9 FirstFirst ... 56789 LastLast
Results 61 to 70 of 85

Thread: Bedini's Linear Current Amplifier

  1. #61
    Quote Originally Posted by Ecancanvas View Post
    Mr Bedini talks about servo amp, summing amp, and comparator. but his Op Amp is only 8 pins so the most he can have is 2 op amps unless one is hidden on the board that you cant see, or he is preforming the summing or servo current sensing an other way.
    "Ecancanvas" You know the previous circuits with the op-amp for current sensing linear amp regulator.pdf

    Guess what "it is a current source too" yes, no op-amp current sensing needed, the output transistor is the current source. So 2 op-amps.

    So the circuit would look something like this Linear Amp Regulator-npn.pdf with 2 op-amps.

    Have a look at these links

    "Joster" Use star grounding. This means run all grounds to a single physical point, for your PCB design. This is also mentioned in the first URL. Star grounding eliminates "earth loops" and stabilizes the circuit.

    A star connection, at the negative pin of the pre-filter cap, and a thick track (thickened with solder) from "battery negative" to the "negative pin of the pre-filter cap".(the 15,000uF one).

    A star connection, at the positive pin of the pre-filter cap, so you don't have "earth loops".

    A star connection at op-amp ground, this eliminates unwanted noise entering the high impedance inputs of the op-amps.

    A star connection at the emitter of the beta multiplier would not hurt, and a nice "thick as short as possible track" (thickened with solder) between the "emitter of the beta multiplier" and the output device.

    If you wish to make extra measures, have star connections on all of the op-amp inputs.
    All the resistors connecting to inputs/"summing points" of the op-amp/s connect to a single point at the input pin/s of the op-amps.

    This is like designing a circuit board for an audio amp.

    I will indicate the star connections on my future schematics.
    Last edited by Nityesh Schnaderbeck; 10-03-2014 at 05:07 AM.

  2. #62
    This is a another current source, this is very similar to the current sensing in my previous schematic, except in my schematic I had a high side current sensing and this circuit in this link uses a low side current sensing.

    This circuit could gives some hints of the linear amp design, too.
    Last edited by Nityesh Schnaderbeck; 10-05-2014 at 01:15 AM.

  3. #63

    Linear amp Regulator, Regulators as audio amps

    I have just been reading the "140 amp solar tracker" thread and John Bedini was talking about linear regulators as a class A audio amp.

    Check it out, super cool. And this circuit works and sounds really good, I had it working on a 12V computer power supply, I changed the 5K adjustable resistor to 1K, and the 10ohm resistor to 39ohm. And used my laptop to supply the music.

    So now to think of the regulators,op-amp and output device as an audio amp. The plus and minus regulators, as phase splitters, to feed the inverting and non inverting inputs of the op-amp. The op-amp drives the output transistor. The feedback from the battery/load is feed into the input of the regulator phase splitter.

    In order to achieve negative feedback between the input and output, The amp needs to be an inverting audio amp.

    So I should be able to make regulators,op-amp and output device into a class A audio amp. Something like this example circuit

    Audio Regulator Amp.pdf

    Current limiting is achieved by R8, (the emitter resistor), Because R8 is inside the negative feedback loop, the voltage drop caused from current, is turning off the output device, in order to limit the current.

    Why do I want to make an audio amp, because it's fun. And this is a big step toward success.

    And here is a link for Class "A" audio amp design.

    This also means looking at the load line of the output device/transistor.
    Last edited by Nityesh Schnaderbeck; 10-10-2014 at 01:43 AM.

  4. #64

    Lightbulb I have a voltage regulator phase splitter working

    Very good news I have just figured out how to bias the voltage regulators, to make a phase splitter.

    Here is the circuit, Voltage regulator phase splitter.pdf Using LM137 and LM337 voltage regulators.

    I have it driving an 8ohm speaker. Just need to replace C1 and C2 for resistors, for use in the "linear amp regulator".
    If the voltage regulators were a matched pair, then the distortion will be less. Still sounds good.

    D1,D2,D3 & D4 can all be replaced by a 2.5V zener (in reverse bias) or the LM336 2.5V precision voltage reference IC.

    Be thankful the small successes, and this will lead to the big success.

    I am working on the "linear amp regulator" stage be stage.
    Last edited by Nityesh Schnaderbeck; 10-11-2014 at 01:02 PM.

  5. #65
    been out for a while, totaled my car, i'm ok and recovering. Looks like I have lots of catch up to do.
    have not had to buy a car in over 10 years, ouch!

  6. #66
    Quote Originally Posted by Ecancanvas View Post
    been out for a while, totaled my car, i'm ok and recovering. Looks like I have lots of catch up to do.
    have not had to buy a car in over 10 years, ouch!
    It's good to know you are ok, happy thoughts for your recovery..It don't matter about the car, your life is more important.

    I am in the process of making, the regulators, op-amp and output transistor and beta multiplier into an audio amp. I am going through each stage to the "linear amp regulator" I have gone the wrong direction a couple of times, and had to reset/reassess my thinking, back to "I know nothing" and start again.

    I have made a simplified diagram to help me and others understand, more about the "Linear Amp Regulator"

    Simplified Diagram.pdf

    Please note, this is only the interpretation of a mere mortal.

    This is missing the comparator, so this diagram may be updated, as I learn about the comparator stage.
    Last edited by Nityesh Schnaderbeck; 10-12-2014 at 03:13 AM.

  7. #67
    Why did you use R5 and R6 in your Voltage regulator phase splitter
    circuit. such low ohms for feedback. so you are sending feed back to pin 1 and pin 3. Im building up your circuit for audio, looks like fun. what are your ideas for attaching the op amp. just spitting out thoughts. I used a 2.5v zener in a circuit simulator and it gives quite different voltages from the 4 diodes.

  8. #68
    Voltage regulator phase splitter.pdf
    I think the 2,5V zener is the better than my 4 diodes connected in series, R5 and R6 are not feedback resistors (R3 and R4 are the feedback resistors), they are to bias the output with the correct voltage, the original circuit from the internet, that lead me to this circuit had 10ohm for this resistor, I changed it to 47ohm, so I don't have to have the regulators on a heat sink. The 2 regulators are operating in class A. One positive "class A" and one negative "class A", they are opposite of each other. And I put the speaker between the outputs, to prove that the outputs are opposite to each other. So I know it is a phase splitter. R5 and R6 are low values only to set the correct bias to drive an 8ohm speaker.

    When this stage is inside the "Linear Amp Regulator" R5 and R6 will be something 1K, 2K, 5K, etc.

    In short this phase splitter circuit, converts an unbalanced signal to a balanced signal. The op-amp converts the balanced signal back to an unbalanced signal.

    I think that in the "Linear Amp Regulator" the plus and minus regulators are phase splitting, so that the feed back from the battery is directly coupled to the op-amp, because the op-amp is operating with balanced inputs on a plus and minus supply of +15V and -15V or so. When the battery is charged and floating then the positive of the battery is the same as the op-amp ground. So it is always trying to pull the battery voltage to op-amp ground. (op-amp ground is held between 30V, so op-amp ground will be 15V same as the battery)

    I could use op-amps and bias them in class A, then I would need to make current sources which will increase the component count, the regulators already have everything inside, just need to get past that internal zener. Just need to cancel out the internal zener with an external zener. The LM317 and LM337 have 1.25V Zeners inside the 2.5V external zener cancels out both these internal zeners. As you could imagine, the better the external zener is matched with both the zeners inside the regulators, the less distortion. The regulators are very much like a class "A" op-amp.

    Have a look at this page about two thirds down the page you will see the LM317 internal schematic When we know whats inside, it will help us design the phase splitter.

    have a look at these links

    I have been also working on a modified version of this circuit.

    "Ecancanvas" Can I ask you what is the simulator you are using?. I have never used a simulator before. I have "protel 2004" with spice, but too many errors to resolve. I think I need to change software. At the moment my imagination is my circuit simulator.
    Last edited by Nityesh Schnaderbeck; 10-13-2014 at 06:13 AM.

  9. #69
    This is an update to the simplified diagram with a comparator, so to add voltage control.

    Simplified Diagram with Comparator.pdf

    To me it would make more sense to do like this. Anyway this is the block diagram, of my circuit goal, at this point in time.

  10. #70

    Complimentary Regulator Phase Splitter Ver.2

    Here is another version of the "Complimentary Regulator Phase Splitter"

    Regulator Phase Splitter Amp Ver2.pdf

    This circuit is easier to modify to amplify DC, when this stage goes in the "Linear Amp Regulator" the capacitors C1 and C2 will be removed. The capacitors are there so I can just use a 12V single rail supply, to make testing easier.


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts