Tubes?

[innovation_station]

marco what is the name of the osc circuit you posted

i have many digital old tube radio books on my laptop with hundreds of schmatics in them

i can have a look and see if i have the same circuit with a better description


is

[turbo]

Hi,
The oscillator is called a Colpitts oscillator.
There is another oscillator in the books which is better but it deals with crystals and therefore it is hard to adjust in frequency.
It is used as an example for a radio transmitter which has to be extremly stable.

Then i think about what steven said about:

"sorry, these are not piezo stacks,however they look like it."

and

"you create several frequency's within a space of the collector coil's circumference"

and when he mentions the tube you own which is actually a Rf amplifier,

"you should hear how crystal clear the frequency's are.....

He talks about cancelling the flux, but would that mean the magnetic flux?
I did read somewhere something about transmitting in order to recieve, and i am doing a little study on the regeneration principle in which the reciever sweeps past and over the center frequency thousants of times per second and they sure notice it's impotant to make sure the local oscillator doesnt go into transmitting mode itself because of interferance with other recievers etc...

Marco.

[z_p_e]

Quote from: -[marco]- on Today at 12:57:18 PM
Hi Darren,
This is simply explained,
The high voltage from the plate transformer is connected to the heater transformer.
but it is only connected to one end of the winding,therefore it is not a closed circuit.
That was a bit confusing to me and as i remember correctly i took a 100kpot in series with a 30k resistor in series between the high voltage output of the tube and the scope.
i was hoping to scale the voltage down and as you know at that point i was not familiar with the shunt circuit you pointed out to me.
Anyway ,the signal was too large to fit the screen of the scope so i decided to disconnect the ground wire.
Beautiful Kicks appeard and i remember thinking this was a bit of a new area to me because i am used to work with the ancient "closed loop"

Marco.


Wow, Marco. Now I'm slightly confused. I think these were some details that may have been worth mentioning a lot earlier  Cheesy  Huh

The high voltage from the plate transformer is connected to the heater transformer.

Yes it is, through the tube rectifier, not directly.

but it is only connected to one end of the winding,therefore it is not a closed circuit.

The tube heater filament, which is also the cathode, is connected to both ends of the filament transformer secondary, so I do not see how this is true.

Anyway ,the signal was too large to fit the screen of the scope so i decided to disconnect the ground wire.

The fact that the signal was still too large makes perfect sense. Which ground wire did you disconnect...the scope ground lead?

If you were then measuring the output with an ungrounded scope, then what was the scope using as a reference? Is your scope battery operated or plugged into the grid?

Even if your scope was powered off the grid, you still would have no reference to your circuit because it is all isolated by the transformers. ?

Help me out please....I don't want to be confused about what you are doing.

Darren

Darren,
The circuit was fed by a truck battery.
The Scope was fed by a seperate car battery.
No Grid connection invloved.
Because i could not see the waveform on the scope, i disconnected the ground wire which normally was on the zero voltage line of the plate transformer.

The tube heater filament, which is also the cathode, is connected to both ends of the filament transformer secondary, so I do not see how this is true.

are you saying the 500VDC is coupled to the heater transformer?
I ask because i still do not completly understand how we can couple 500VDC on top of the 5VAC.
as i look at the drawing it seems as if the high voltage which is also the output, is connected to one end of the filament only.

Marco.

OK, so you lifted the centre-tap from ground on the plate transformer secondary, and it was floating, correct?

Yes, the +500V tube output is connected-to and "riding-on" the 5VAC filament voltage on the filament secondary in this case. Question: can you have two inductors in series, drive a different AC signal into each end and measure something in the middle where they are connected?...Yes, of course. Can you then change one AC source to a DC source and still measure something at their connection?..Yes, you still can.

Yes the output is connected to one side of the filament transformer secondary, but the rectified output is available at either side, so it does not matter. It all forms a closed circuit.

Darren

PS. Let me see if anything goes funny if I lift the centre-tap ground in my sim.

[innovation_station]

well a long time ago i mentioned crystals because of there overtones and there ability to osc from magnetic waves also as filters but there some programable crystals out there thouse and the use of an atmega 128 chip {the free tv ones }  i found a pattened a long time ago regarding what i felt at the time was the controler pattened for the tpu and i posted it since then i have gone through 2 computers crashing and stuff and i deleted my post of it there was a total of 12 pattends i found but saw them all only twice and managed to fins only 3 or 4 agin the othere were never found agin and i spent many hours looking

now im looking for a circuit that meets that criculam
from the old books
for a simple tube osc it might be possible that it is really only 1 freq used in the tpu and simplu modified varryations of

a question has any one plused the same freq in 2 dirrections at the same time?? ?? ?? in the same coil?? if so outcome?

and if we put a crystal in the mix to make an overtone of the freq  we would have more interactions in the same wire the higher harmonics


and if we put 2 crystals with diodes 1 for positive and 1 for negitive harmonics would we not at some point saturate that collector wire with a supream amount of kicks

ok i realy have to stop thinking

im looking

[z_p_e]

Well, I lifted the centre-tap ground and of course it didn't work.

With only 2 diodes, there is no reference point. You need 4 diodes if your secondary is fully floating such as would be the case here. All I saw was a tiny sine wave at the output...about 50mVp....so no surprise.


So Marco, I'm not sure what you were getting there. To be honest, it all looks ok except that you had no filter, yet clearly it is filtered, and second, you had the kicks, which is a mystery right now.

Looking forward to seeing your second round of test measurements.


Darren