Hello. I'm going to make a triode tube. The question is I don't have idea about how to test it. I mean, how much voltage do I have to apply between cathode and anode and in the grid.

Of course it's depend on the construction of the tube, but I'd like to know between what values I should move.

Thank you

Best regards

 

Why?

 

You can find someone online with a tube tester that will test it for you by post.

 

Can you reach near absolute vacuum?

 

Folks have built tube circuits operating at 12V.

 

Paschens law should be considered here. It's no small feat in building a vacuum triode.

 

Can you reach near absolute vacuum?

It's interesting that the inventor of the triode valve, Lee de Forest, thought that there needed to be a small amount of air in the tube to carry the electrons between the electrodes.

 

Why?

Why not? I like to make things

Can you reach near absolute vacuum?

0,05 microns and also I´ll use a titanium getter to go lower.

Folks have built tube circuits operating at 12V.

Ok, that is a starting point! Thank you

 

There are quite a few utube videos on making and testing your own tubes.

 

Do you have a device in mind for the use of your triode?

 

There are quite a few utube videos on making and testing your own tubes.

Yes, I have seen these videos. In youtube for example jdflyback and glasslinger, but besides they explain veeeery well how to make the tube, when they test the tubes, they don´t explain too much. Just some needles moving, confirming that the tube works, but nothing avout voltages and currents.

Do you have a device in mind for the use of your triode?

Not for this first one. Jus making a tube. In the future, I´d like to make a radio

 

Was just reading the wiki, very interesting. Powering the tube

 

Take a look @ WorldRadioHistory: Radio Music Electronics Publications ALL FREE. It has many old books both cataloging tubes and on their design.

 

Why not? I like to make things

I asked the question why because the design (voltage, gain, frequency response, etc...) of the tube depends on its intended usage. You can design 'space-charge' tube that operate at 12 volts or shunt regulators that operate at thousands. So your initial question was far too broad for a proper answer. If you have the proper vacuum apparatus, making a tube is trivial, it's making the tube that's a challenge.

What's your experience level with tube circuits?

 

Was just reading the wiki, very interesting. Powering the tube

Thank you, there are some values in the article.

Take a look @ WorldRadioHistory: Radio Music Electronics Publications ALL FREE. It has many old books both cataloging tubes and on their design.

Thank you!! there are a lot of maerial, it will be useful for the radio project also.

I asked the question why because the design (voltage, gain, frequency response, etc...) of the tube depends on its intended usage. You can design 'space-charge' tube that operate at 12 volts or shunt regulators that operate at thousands. So your initial question was far too broad for a proper answer. If you have the proper vacuum apparatus, making a tube is trivial, it's making the tube that's a challenge.

What's your experience level with tube circuits?

Ah ok, sorry, I´m still learning english. Ok I don´t have any experience

 

Here is how you test it:

Get two power supplies, 0 to 150V and 0 to -10V and a mA meter.

Setting grid voltages of 0, -1, -2 etc. Sweep the anode voltage from 0 to 150V, taking current readings and plotting a set of curves like this:

12AX7 characteristic curves

 

Sure, you can build a radio using a vacuum tube. But why bother when a FET can do the same thing as a tube.
Here is my circuit for a simple radio using a FET as an RF amplifier. Buena suerte!

 

Here is how you test it:

Get two power supplies, 0 to 150V and 0 to -10V and a mA meter.

Setting grid voltages of 0, -1, -2 etc. Sweep the anode voltage from 0 to 150V, taking current readings and plotting a set of curves like this:

12AX7 characteristic curves

Thank you!

Sure, you can build a radio using a vacuum tube. But why bother when a FET can do the same thing as a tube.
Here is my circuit for a simple radio using a FET as an RF amplifier. Buena suerte!

It is not about the destiny but about the journey. I like making things from 0

 

Here is my circuit for a simple radio

Out of curiosity, what are the specs on T1?

 

Out of curiosity, what are the specs on T1?

This is homemade DIY coil of about 48 turns wound on the cardboard from a roll of toilet tissue.
The secondary is about another 100 turns on a slightly smaller diameter cardboard tube that slides inside the primary.
You slide one over the other to change the inductive coupling for best performance.

You can follow the discussion here:

https://forum.allaboutcircuits.com/threads/documenting-a-trf-radio-build.172228/