calculating proper base resistors

[Ren]

Hi RS,

Any chance you have that schematic in a larger size? Im getting thumbnail resolutions.

Just out of interest (I like to approach a problem from both sides) you mentioned "or group of 4 transistors can not hog all the trigger current for what ever reason. "

Can you elaborate on that "reason" at all? Is it things like longer than necessary conductors linking the circuit adding resistance or impedance or are there other factors in play?

And perhaps you could offer P'n'S (and myself) some advice regarding a question that was raised in another thread regarding the matching of transistors. In regards to the Bedini Cole circuit we were uncertain about the protocol for matching the PNP, does the Beta matching circuit and procedure match the NPNs?

Regards

[John_Bedini]

Here is the correct drawing, and just because Ralph's machine worked out this way does not mean your machine is going to do the same.
"Do not in any circumstances put resistors in series with the coils on the power windings".

John B

[LesK]

Here is the correct drawing, and just because Ralph's machine worked out this way does not mean your machine is going to do the same.
"Do not in any circumstances put resistors in series with the coils on the power windings".

John B

[ATTACH=CONFIG]110[/ATTACH]

Thanks John,
This makes so much more sense to me. I am looking at this such that we want just sufficient current to turn the transistor fully on without wasting energy and with the resitor network to happen all at the same time. It also looks like we want the voltage at the base to just peak above 0.7 volts to set the on time of the transistor to match the coil. That is to say as Paul Babcock described, to give the coil just enough energy to fully charge but not over charge. This is my thinking so far anyway, and this is why I think every build is different. Because we all wind our coils slightly different. In fact getting one person to wind six coils identical is real task....! One I am about to attempt....

The next thing I am trying to understand here is the interaction between the trigger strand and the driving strand. And since we also have a magnet doesn't that give us a magneto? I am sorry to go over this again for the trilianth time, you have given us all this for years. But after four years of playing with this, Like I told John k. I am now a qualified infant in the technology..... Suddenly the basics look very different to me than even just a month ago, When I really began to start thinking about the core. And what Howard Johnson said about the gate and two pulses. I think I have a grasp of the electronics at work here but when it comes to what the magnet and core are doing I still get a little lost. That is what has instilled in me the desire to build this as accuratly as possible. More because of what I don't know than what I do.....


Thanks again Everyone
Les

[LesK]

Here is the correct drawing, and just because Ralph's machine worked out this way does not mean your machine is going to do the same.
"Do not in any circumstances put resistors in series with the coils on the power windings".

John B

[ATTACH=CONFIG]110[/ATTACH]

Thanks John,
This makes so much more sense to me. I am looking at this such that we want just sufficient current to turn the transistor fully on without wasting energy and with the resitor network to happen all at the same time. It also looks like we want the voltage at the base to just peak above 0.7 volts to set the on time of the transistor to match the coil. That is to say as Paul Babcock described, to give the coil just enough energy to fully charge but not over charge. This is my thinking so far anyway, and this is why I think every build is different. Because we all wind our coils slightly different. In fact getting one person to wind six coils identical is real task....! One I am about to attempt....

The next thing I am trying to understand here is the interaction between the trigger strand and the driving strand. And since we also have a magnet doesn't that give us a magneto? I am sorry to go over this again for the trilianth time, you have given us all this for years. But after four years of playing with this, Like I told John k. I am now a qualified infant in the technology..... Suddenly the basics look very different to me than even just a month ago, When I really began to start thinking about the core. And what Howard Johnson said about the gate and two pulses. I think I have a grasp of the electronics at work here but when it comes to what the magnet and core are doing I still get a little lost. That is what has instilled in me the desire to build this as accuratly as possible. More because of what I don't know than what I do.....


Thanks again Everyone
Les

[RS_]

See below.....

Hi RS,

Any chance you have that schematic in a larger size? Im getting thumbnail resolutions.

I tried to put it in a photo album but it re-sizes it to small....... if you want a full size pic, just PM me with a email address, and i will send it to you

Just out of interest (I like to approach a problem from both sides) you mentioned "or group of 4 transistors can not hog all the trigger current for what ever reason. "

Can you elaborate on that "reason" at all? Is it things like longer than necessary conductors linking the circuit adding resistance or impedance or are there other factors in play?
yes for all the reasons you listed, plus differences in the trannys them self's, and other Factors that JB should elaborate on

And perhaps you could offer P'n'S (and myself) some advice regarding a question that was raised in another thread regarding the matching of transistors. In regards to the Bedini Cole circuit we were uncertain about the protocol for matching the PNP, does the Beta matching circuit and procedure match the NPNs?

On smaller transistors like the BD243C-BD244C, I use the hFE tester on my meter and try to get them as close as possible, the MJL's are to big for my meter to read well...... hFE testers could be built for them though.... a curve tracer set up for both should work as well...... and I have had good success using complimentary matched pairs from the factory, in the motorola 3055-2955 trannys, and in the NTE brand of the same size.
I do not know if the MJL's come in complimentary matched pairs from the factory or not..... it would be great if they did..........
When they are not matched well, the top PNP tranny will run Hot..... when you got it right, they both will run cold to the touch........

RS
Regards

[RS_]

Oh yea, on the MJL NPN PNP's I measure the voltage drop's between the 3 pins, and select the closes match between the NPN and PNP, and that can be a few points different between them

[min2oly]

And perhaps you could offer P'n'S (and myself) some advice regarding a question that was raised in another thread regarding the matching of transistors. In regards to the Bedini Cole circuit we were uncertain about the protocol for matching the PNP, does the Beta matching circuit and procedure match the NPNs?

On smaller transistors like the BD243C-BD244C, I use the hFE tester on my meter and try to get them as close as possible, the MJL's are to big for my meter to read well...... hFE testers could be built for them though.... a curve tracer set up for both should work as well...... and I have had good success using complimentary matched pairs from the factory, in the motorola 3055-2955 trannys, and in the NTE brand of the same size.
I do not know if the MJL's come in complimentary matched pairs from the factory or not..... it would be great if they did..........
When they are not matched well, the top PNP tranny will run Hot..... when you got it right, they both will run cold to the touch........

RS
Regards

This is exactly what I experience with an unmatched pair the pnp runs hot, however, I find it extreemly rare to be able to match the pnp to the npn, and in addition get 3 of each to all match
I was hoping the "220 ohm" resistor (Bedini-Cole ckt) was there to help with this function so that if we get the pnp and npn in close range, it might be enough???
do you mind posting where you purchased the Motorolas? Having difficulty finding anyplace that will sell a matched pair...
Thanks,
Patrick

[RS_]

min2oly
I bought old stock Motorola's, you are not going to find them any more unless your really lucky.... On Simi bought Motorola's transistor division a good while back and i dont know what they sell as far as complimentary pair's, but they may have MJL pairs, i just have not looked for that.......

the NTE Brand has the TO3 case NTE130 and the NTE219 that = the 2N3055 and 2N2955, that can be bought as matched pairs

[RS_]

Min2oly and all,

I just chatted with ON Simi, and they Do Not sell factory matched complimentary pair's of the MJL21193 / MJL21194.....

so it's up to us to match them up.........

[Mike Klimesh]

Complimentary pair's of the MJL21193 / MJL21194

Hi All,
When I tried matching the MJL's for the Ferris Wheel circuit the hundred 94's I got were between 20 and the low 30's and the 93's were in the 80's. Not good

I found a guy that uses a Tektronix 576 Curve Tracer and will match them.
I brought "On-Semi MJL21193 and MJL21194 Matched Triplet" from him which gave me 3 of the 94's and 3 of the 93's that were all at 52 when I checked them on my hFE tester . Now I'm happy (+_+)

He can also supply 8 matched 94's which is nice for the monopole circuit.

I found him at
Tech DIY Company Store

Mike Klimesh

[min2oly]

That's fantastic!
Just ordered a matched triplet :-)
Sweet...
Thanks Mike!
sincerely,
Patrick