Siemens GI. 1,5

Hi all,

Does anybody kow about Siemens GI. 1,5 tube?

It seems to be a full wave rectifier. Not gas filled as did not react to the Tesla generator.

• IMG_20250826_184730 (341 KB)
• IMG_20250826_185317 (539 KB)

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Hello Ottó,

it's this tube: Gl.1,5* - note the * !

I can't tell anything about the gas filling (or not), - if possible, just test it under normal operating conditions.

Best Regards,
Jacob

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Hello Jacob,

Thank you. I don't know why the tube search for GI.1,5 gives only russian tubes.

According my measurements Vf 1,5V gives 4.5A heating current, and the rectifier don't work.

Around Vf 2.7V and If 6.4A it starts to work. Are you sure the heating data is correct in its page?

I don't see any colouring when it works. So I don't know anything about the gas filling, but without gas filling it will not give so high rectified current.

Otto

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Hello Ottó,

The Gl.1,5* is an upgrade of the Gl.1,5 (without *).

On the Gl.1,5 page, a data table specifies a heating voltage of 1.45–1.5 V and a heating current of 7 A.

Therefore it's normal to start working once a heating current of 6.4A has been reached.

A voltage drop seems to happen, probably due to poor soldering in the base pins.

Gl. stands for Gleichrichter = rectifier, 1,5 stands for the available direct current of 1.5 A.

Jacob

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Hello Ottó
If you search for  GI.1,5 (gi 1,5) you will find the russian tubes.
Please look for GL1.5

Otmar

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Hi Jacob and Otmar,

Thank you for the answers. Yes, the soldering problem can cause the heating voltage increase. 

So, the right type is Gl. 1,5 * (GL. 1,5*) instead of Gi. 1,5* 

I detected. It's argon filled. Using a Tesla generator, and place it closest to the highest voltage it glows in blue-violet. 

Ottó

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