Bedini's Linear Current Amplifier

[Ecancanvas]

Modified Nityesh Schematic rev 3.pdf


Rev 3 has just a few of Nityesh's suggested changes. just some pictures of what I'm playing with.
Using 2 device switch because of what batteries i have. I have a box of cap-pulsers switches and this switch charges up batteries faster. it draws 200ma. i will spend some time over weekend and get a little more info on wheel drag(Rpm). This switch is not operating like Johns was in the video.(yet) John used fewer parts and achieved something special. If enough of us keep playing around with it and making improvements i think we can get there, or something very close.

[Joster]

Ecancanvas, awesome work!!

here is the progress on the pcb from Nityesh's schematic top and bottom layers...need to make the high current path trace alot bigger and check layout with print out and actual components....and feedback would be great

[Lman]

Lman, do you have a schematic that can help move things in that direction?

Joster,

Schematic would not help if you do not learn how the emitter follower works. In the other thread started by you I have posted two links (long ago) explaining it perfectly.

This design has PNP output transistor and a resistor, on the emitter. I am taking the output from the collector. If this Means changing this to an NPN output transistor, and taking the output from the emitter.


This is very a simple mod.

For NPN output transistor, swap pin5 and pin6 of IC1B, and connect the collector of the NPN to R15 and the emitter to the positive of the battery.

Nityesh,

Thinking conventional current flow the most of the current flowing in a transistor is through the emitter.
Emitter follower can be done with either NPN or PNP if you take the power from the emitter. But the gain of the transistor and the emitter resistor are important for the correct current gain and output impedance.
The emitter follower (called also common collector) is the one that will give you current gain.


Just wanted to give you a little push into the right direction.


Regards
Lman

[Nityesh Schnaderbeck]

Nityesh,

Thinking conventional current flow the most of the current flowing in a transistor is through the emitter.
Emitter follower can be done with either NPN or PNP if you take the power from the emitter. But the gain of the transistor and the emitter resistor are important for the correct current gain and output impedance.
The emitter follower (called also common collector) is the one that will give you current gain.


Just wanted to give you a little push into the right direction.


Regards
Lman

"Power from the emitter", Like with the beta multiplier. The emitter arrow says one direction only. About the emitter resistor, if this has all the current flowing though it, then this would be kept at low value, maybe 0.1ohm or something.

The base emitter current, is flowing through the resistor and the battery. So any voltage changes in the battery and resistor, will also make changes in the base emitter current. This current is then multiplied by the gain of the transistor.

Is this a like a current source?

Is this how impedance sensing is done?

Thanx in advance.

[Nityesh Schnaderbeck]

Some thing else about the circuit, I need a dual tracking voltage reference, with offset adjust. So the outputs of the regulator, are the same but opposite. (with respect to op-amp ground).

An adjustable voltage mirror.

My current design has no dual tracking in the regulator stage, which defeats the purpose of having a plus and minus regulator.



More fun, more designing, cool.

[Tom C]

stay single sided on the circuit boards. you get cross inductance with hi potentials, especially pulsed ones, on dual sided boards. it cans crew everything up.

Tom C

[Nityesh Schnaderbeck]

stay single sided on the circuit boards. you get cross inductance with hi potentials, especially pulsed ones, on dual sided boards. it cans crew everything up.
Tom C

Thankyou, for your good advise, I could imagine capacitance's also with double sided.

Where do you think the star connections should go?.

[Nityesh Schnaderbeck]

Dual Tracking voltage regulator has one adjustment to adjust 2 identical opposite voltages, one +ve voltage and one -ve voltage, as far as I know these voltages are fed into a balanced input amplifier.

And as far as I know this turns the balanced DC signal into an unbalanced amplified DC signal.

This would be a very smooth regulator.

[Joster]

Dual Tracking voltage regulator has one adjustment to adjust 2 identical opposite voltages, one +ve voltage and one -ve voltage, as far as I know these voltages are fed into a balanced input amplifier.

And as far as I know this turns the balanced DC signal into an unbalanced amplified DC signal.

This would be a very smooth regulator.

[ATTACH=CONFIG]3858[/ATTACH]

Thanks Tom C! Will revise!

[Ecancanvas]

Nityesh and Joster,
I have been giving some thought to the 2 regulator circuit. it might be as simple as adding an other cap and feeding reg 2 from between the 2 caps. I need to breadboard just the regulator circuit and play around with it so we can get a 24v differential.
in Johns video 37 he states that the amp must be a transistor because a fet won't work. My question is what is it that makes the fet not work and why is the transistor better for this application. i was also looking at the leads on Johns circuit and it appears that the center leg is feeding the battery so would that not be a PNP transistor?
Having to much fun

[Tom C]

you guys are doing great!! just a note here, remember the more components you have, the more you deal with voltage drops and current consumption. make your goal to be as elegant as possible using as few components as possible.

Aln mentioned emmiter follower: http://www.transtutors.com/homework-...-follower.aspx

Tom C

[Joster]

you guys are doing great!! just a note here, remember the more components you have, the more you deal with voltage drops and current consumption. make your goal to be as elegant as possible using as few components as possible.

Aln mentioned emmiter follower: http://www.transtutors.com/homework-...-follower.aspx

Tom C

so the low output impedance of the emitter follower goes on the back end to allow maximum current into the battery or load correct? So all we need to do is swap out that pnp darlington pair with an npn power transistor and add some emitter resistance then connect the charge battery in parallel across the emitter resistance. But that will cause the battery to want to discharge through that emitter resistance but that is where the output is from an emitter follower is according to the above link....so confused!

[Tom C]

you still need the darlington....


Tom C

[Nityesh Schnaderbeck]

I have come across some information that will help us understand the beta multiplier, So the beta multiplier simulates a big capacitor of a higher value by multiplying a small capacitance.

Have a look a the "Gyrator Circuit" (search in Google)

A gyrator is a circuit which transforms reactances. Normally gyrators are used to simulate inductors, since inductors are often expensive and bulky.

And with can be modified to simulate/multiply capacitance. Since inductance and capacitance are inverse of each other.

http://www.daycounter.com/Circuits/G.../Gyrator.phtml

Look familiar.

[Ecancanvas]

Hey all,
I believe it is the PNP we need to use to feed the battery, i don't know that it needs to be a darlington pair maybe, if you go to
http://www.allaboutcircuits.com/videos/74.html by the example of the op amp internal circuit. the v+ power feed comes in and runs through a single PNP. the professor sz its a transistor being used as a resistor to control current pick up the video around 1:15. The PNP is being used as a resistor for current. Mr Bedini shows the amplifier circuit feeding the battery, and he draws out a op amp on the white board.
don't we want that circuit to regulate the current, the Beta circuit is controlling the voltage..... and providing the current(not controlling)