Bedini SG - The Complete Intermediate Handbook

[Aaron Murakami]

Bedini SG - The Complete Intermediate Handbook has been released!


http://www.emediapress.com/go.php?offer=energysci&pid=38

[emfimp]

Thank you John B., Peter, and Aaron for this series of books! These are a greater resource than I could have imagined, and I am very grateful for your taking time to share these amazing discoveries with all of us.

I have a couple of questions on the transistor matching device - just finished putting mine together a couple days ago, and it works great! Most of my MJL 21194's will only read about 25 to 30 mA with the potentiometer at minimum resistance - is this normal? The book seemed to suggest that I should be able to get 250 mA, and at a minimum, 100 mA. Using MJE 3055's, many more will reach 150 mA, or rarely 180 mA, but most of those center around 100 mA, with the pot maxed (minimum resistance).

I realize that it is the relative measurement that is important - I'm just wondering why my readings are so different from the published results. Would I be better off changing some of my resistors to lower values, to allow for more current flow?

Also, I'm wondering about measuring PNP transistors. Looking at the diagram, I realized that I could probably just switch the positive post to be the negative post, and switch the negative to a positive. (obviously the meter would have to be reversed as well) Is this how John B does it? I just used a DPDT switch after the momentary pushbutton, and after the ammeter to accomplish this, as in the photos below.



My purpose in doing this is that I am trying to build a Bedini-Cole Sequential Bipolar Switch, and am having some difficulties finding matching transistors. I did the test as you mentioned in the book and found my "Calibration 100" transistor. This was an MJE 3055, and then with that calibration, just flipped the switch to change polarities (for PNP), and measured all my MJE 2955's. Handy!

It seems like all the transistors that I have are made in batches, with most of the batch falling into a relatively close range. That batch may vary from another batch by a lot, though. So in testing my PNP's (MJE 2955), I find their gain to be very different from my NPN's (MJE 3055), and not enough variance within the group to get two transistors that are close. The closest gap was around 30 mA, which is fairly large. I imagine this will create an unwanted effect in the circuit, is this true? I've gone through 40 plus of these transistors without finding anything that is closer matching - do I simply need to test more?

Is there an alternative solution to buying and testing more, like changing the resistor values slightly to compensate? Or is the switching in the circuit fast enough that it won't make a large difference in switching times?

Thank you for sharing your efforts and talents with us!
Daniel

[Retep]

Variations on the Transistor Matching Meter

Thank you John B., Peter, and Aaron for this series of books! These are a greater resource than I could have imagined, and I am very grateful for your taking time to share these amazing discoveries with all of us.

I have a couple of questions on the transistor matching device - just finished putting mine together a couple days ago, and it works great! Most of my MJL 21194's will only read about 25 to 30 mA with the potentiometer at minimum resistance - is this normal? The book seemed to suggest that I should be able to get 250 mA, and at a minimum, 100 mA. Using MJE 3055's, many more will reach 150 mA, or rarely 180 mA, but most of those center around 100 mA, with the pot maxed (minimum resistance).

I realize that it is the relative measurement that is important - I'm just wondering why my readings are so different from the published results. Would I be better off changing some of my resistors to lower values, to allow for more current flow?

Also, I'm wondering about measuring PNP transistors. Looking at the diagram, I realized that I could probably just switch the positive post to be the negative post, and switch the negative to a positive. (obviously the meter would have to be reversed as well) Is this how John B does it? I just used a DPDT switch after the momentary pushbutton, and after the ammeter to accomplish this, as in the photos below.

[ATTACH=CONFIG]1725[/ATTACH][ATTACH=CONFIG]1726[/ATTACH]

My purpose in doing this is that I am trying to build a Bedini-Cole Sequential Bipolar Switch, and am having some difficulties finding matching transistors. I did the test as you mentioned in the book and found my "Calibration 100" transistor. This was an MJE 3055, and then with that calibration, just flipped the switch to change polarities (for PNP), and measured all my MJE 2955's. Handy!

It seems like all the transistors that I have are made in batches, with most of the batch falling into a relatively close range. That batch may vary from another batch by a lot, though. So in testing my PNP's (MJE 2955), I find their gain to be very different from my NPN's (MJE 3055), and not enough variance within the group to get two transistors that are close. The closest gap was around 30 mA, which is fairly large. I imagine this will create an unwanted effect in the circuit, is this true? I've gone through 40 plus of these transistors without finding anything that is closer matching - do I simply need to test more?

Is there an alternative solution to buying and testing more, like changing the resistor values slightly to compensate? Or is the switching in the circuit fast enough that it won't make a large difference in switching times?

Thank you for sharing your efforts and talents with us!
Daniel

Daniel,

The meter as it is shown in the book can be used for either Fets or bi-polars. Obviously, Bi-polars need more drive, so you can just put a jumper wire across the 27K to essentially take it out of the circuit. At that point, you should be able to get much higher readings on your NPNs. Also, since the PNPs have lower gain than the NPNs as a general rule, just pick the highest gain PNP you can find, and then look for a lower gain NPN to match. Hope that helps.

Peter

[LesK]

Thoroughly enjoyed the book. Very well written. This is what we needed a very long time ago, but am just glad it is here now.
On my meter I added some resistors in parallel until I got it about where I wanted it. If you simply remove the resistor and put a wire there you could ruin your meter.
The info on the caps was great to read about. I have a lot going on right now but will have some questions later.

My Thanks once again to John Bedini, Aaron, Peter, and any others that have contributed to this work...
Les

[emfimp]

Thanks Peter! That works well!

All my 3055's definitely do have a higher gain than my 2955's. Strangely, the 21193's that I have show a higher gain than the 21194's.

BTW, on the end of page 40 / beginning of 41, it is mentioned about being able to purchase a "ready built" cap discharge circuit of John Bedini's design - are these available presently? I'd be very interested in one of these to play with!

Good point Les - I've certainly done my fair share of frying stuff! lol

Thanks,
Daniel

[Aaron Murakami]

a "ready built" cap discharge circuit of John Bedini's design - are these available presently?

Daniel,

We'll announce these as soon as they're available. Maybe in the next few weeks.