The SG Radiant Oscillator

[RS_]

yes thank you

i have also seen another one from JB that looks closer to what i posted with a transistor, and is close to what i see on some units Shunts that i have studyed....

[Dave Wing]

if we can find that one Pic JB has posted.... i can draw the wave form....

RS,

This may be what you are looking for?


Dave Wing

[min2oly]

1. Does this only happen with an inductive load (coil)? How about with a majority resistive or capacitive load?

I think only with inductive loads, (think Tesla and switching the long DC power lines), and current lagging the voltage happens when pos current flows, and is not the same thing as the neg current flow period

2. Where is the current shunt located? Between emitter and ground? Between collector and coil/diode junction? Between coil and battery?

current shunt is in the Neg power line as close to the transistor as ya can get.

3. Is this the result of negative resistance in the barrier as holes and electrons migrate toward each other? Is this caused by a reverse avalanche phenomenon even though the collector is still positive compared to the emitter?
I am not sure what causes it, but the faster the trigger turn on signal, the more pronounced the effect, and a really fast turn off helps too. and with full V across the coil, during that neg flow time period, what is happening...? (think Tesla and switching the long DC power lines)

Does this happen in both rotored and solid state modes?

Yes, but is more pronounced in the rotored versions, because the wave shape is very different from a SS version and why JB liked the rotored versions best, because otherwise, why bother with a rotor with moving parts machine...

4. In your drawing the time function begins at (I assume) the exact time the .6 volt barrier function is reached and the full supply voltage appears across the coil?

YES and the sharper and harder you can do this the better.... (Think Micro Wave level of switching speeds) where the Rotor's Magnetic Flip through the coil core, is Very fast like a snap that the trigger winding applys to the Base, and the Solid State models have a hard time replicating that wave form.....

I think I have shunt in wrong spot, just read this post...

[RS_]

1. Does this only happen with an inductive load (coil)? How about with a majority resistive or capacitive load?

I think only with inductive loads, (think Tesla and switching the long DC power lines), and current lagging the voltage happens when pos current flows, and is not the same thing as the neg current flow period

2. Where is the current shunt located? Between emitter and ground? Between collector and coil/diode junction? Between coil and battery?

current shunt is in the Neg power line as close to the transistor as ya can get.

And a edit: Also looking at a shunt between the Source and the coil will show you a different wave form....

3. Is this the result of negative resistance in the barrier as holes and electrons migrate toward each other? Is this caused by a reverse avalanche phenomenon even though the collector is still positive compared to the emitter?
I am not sure what causes it, but the faster the trigger turn on signal, the more pronounced the effect, and a really fast turn off helps too. and with full V across the coil, during that neg flow time period, what is happening...? (think Tesla and switching the long DC power lines)

Does this happen in both rotored and solid state modes?

Yes, but is more pronounced in the rotored versions, because the wave shape is very different from a SS version and why JB liked the rotored versions best, because otherwise, why bother with a rotor with moving parts machine...

4. In your drawing the time function begins at (I assume) the exact time the .6 volt barrier function is reached and the full supply voltage appears across the coil?

YES and the sharper and harder you can do this the better.... (Think Micro Wave level of switching speeds) where the Rotor's Magnetic Flip through the coil core, is Very fast like a snap that the trigger winding applys to the Base, and the Solid State models have a hard time replicating that wave form.....
Edit,
using a duel trace scope and Looking at a Linear Hall Effect Magnet field sensor on the coil, while looking at the Voltage and/or current wave forms at the same time, is quite illuminating as well. Having more than 1 scope is very helpful......

[Gary Hammond]

Hi RS,

here is a PDF with a hand drawn current wave form like the one JB posted. hope the PDF works

I also added a Collector / Emitter Voltage wave form for clarification that is not on JB's pic
I would like to find the web page with this current wave form and review what JB was talking about where it is posted

That's pretty interesting!

Questions:

1. Does this only happen with an inductive load (coil)? How about with a majority resistive or capacitive load?

(Looks something like current lag in an inductor.)

2. Where is the current shunt located? Between emitter and ground? Between collector and coil/diode junction? Between coil and battery?

3. Is this the result of negative resistance in the barrier as holes and electrons migrate toward each other? Is this caused by a reverse avalanche phenomenon even though the collector is still positive compared to the emitter? Does this happen in both rotored and solid state modes?

4. In your drawing the time function begins at (I assume) the exact time the .6 volt barrier function is reached and the full supply voltage appears across the coil?

Sorry for all the questions. Just trying to figure out if this is due to inductive reactance, trigger current, or some other phenomenon.

[RS_]

here is a PDF with a hand drawn current wave form like the one JB posted. hope the PDF works

I also added a Collector / Emitter Voltage wave form for clarification that is not on JB's pic
I would like to find the web page with this current wave form and review what JB was talking about where it is posted

[min2oly]

if we can find that one Pic JB has posted.... i can draw the wave form....

I don't think I have ever seen anyone post a negative flow at "turn on" by anyone else including JB.

You mention earlier "some units show it real good and a very high neg flow for a long time, some other units show it barely happens."

can you post a link to one so I can have a better idea?

[RS_]

oops corrected thanks

[RS_]

if we can find that one Pic JB has posted.... i can draw the wave form....

[min2oly]

Patrick,
Nice video, but not quite what I ask for....
Can you see the negative current flow at turn on, using a 5A 75mA current shunt, with a scope across the shunt where you would normally put the current meter? Measure without a meter on the shunt, as your scope is the meter.... Not across the transistor collector / emitter voltage.....

some units show it real good and a very high neg flow for a long time, some other units show it barely happens.

do not try to look at the voltage across the collector / emitter, while looking at the current flow across the 5A 75mA current shunt with a duel channel scope, your scope will not like that.....

I have found that some models of hall effect (non invasive) current sensors work good for seeing this neg transistor current effect....

can you show me what you are looking for?

[RS_]

Faraday,

Unfortunately, none of those links had the Neg current flow through the transistor at turn on Pic.....

[RS_]

Patrick,
Nice video, but not quite what I ask for....
Can you see the negative current flow at turn on, using a 5A 75mV current shunt, with a scope across the shunt where you would normally put the current meter? Measure without a meter (just a 75mA volt meter)on the shunt, as your scope is the meter.... Not across the transistor collector / emitter voltage.....

some units show it real good and a very high neg flow for a long time, some other units show it barely happens.

do not try to look at the voltage across the collector / emitter, while looking at the current flow across the 5A 75mA current shunt with a duel channel scope, your scope will not like that.....

I have found that some models of hall effect (non invasive) current sensors work good for seeing this neg transistor current effect, and you can still see the collector / emitter voltage on the other channel....

[min2oly]

Patrick, can you see the negative current flow at turn on, using a current shunt, with a scope across the shunt....?

some units show it real good and a very high neg flow for a long time, some other units show it barely happens.

do not try to look at the voltage across the source while looking at the current flow across the current shunt.... your scope will not like that.....

I have found that some models of hall effect current sensors work good for seeing this neg current effect....

How does this look, I have others that show the neg spike more pronounced, have to look for them a bit more.

[RS_]

Patrick, can you see the negative current flow at turn on, using a current shunt, with a scope across the shunt....?

some units show it real good and a very high neg flow for a long time, some other units show it barely happens.

do not try to look at the voltage across the source while looking at the current flow across the current shunt.... your scope will not like that.....

I have found that some models of hall effect current sensors work good for seeing this neg current effect....

[min2oly]

Hi,

One of the things about the differences between the forced trigger, and the free running trigger with a rotor, is the signal shape.

A rotor trigger strand makes the transistor go into a negative current flow through the transistor right at turn on, thus having the full source voltage across the Coil for a very much longer time period, until forward current flow happens. This opens up the "reaction cross section" (think the Standard Math that integrates the Polyting flow as a circle, now integrating the Polyting flow over an ellipse, that has more surface area to collect the Heaviside current flow) so that the coil can capture more of the Heaviside flow, during turn on while there is negative current flow through the transistor, and then have a very much Higher V Spike at turn off.

It is very hard to get a forced trigger to have the correct Wave form, to have the negative current flow period in the transistor at turn on. This is why JB preferred the Rotor versions to the solid state versions.

JB has shown the Transistor Negative Current Turn On Wave Form on one of his web pages (I think the one with Grabrial Kron)

Most of the transistor manufactures do their darnedest to get rid of the Negative current flow at turn on phenomenon, and try to use fly back diodes, etc... to clamp down the Turn Off Spike, and is why JB recommends certain part number transistors for his various versions of his circuits....

my CPD modded "forced trigger" makes the "neg wave" without effort.