Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [tube]

The word "tube" may refer to a broad range of engineering items, including electron (vacuum or gas) tubes.

Electron tubes

Anything related to electron (vacuum or gas) tubes, i.e. electronic devices where beams or flows of electrons are manipulated with electric fields generated by metallic electrodes inside a sealed glass bulb filled with inert gas or in which vacuum has been made.

Before the widespread diffusion of semiconductor devices, tubes were used in the same roles as amplifiers, rectifiers, switches, logic gates, etc. Nowadays their use is limited to very specialized fields (e.g. very high power RF amplification, X-ray generating tubes, radiation detection tubes, etc.)

See also Wikipedia on electron tubes.

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Why is there a winding on a capacitor?

I just came across this tube RIAA preamp on which there is a coil on the input capacitor, can someone please explain what's the reason of such thing? The schematic and the actual circuit bellow. The site with the full circuit and details is:…
Gabriel Santos
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Vacuum tubes heaters supply, AC or DC?

Which way is better to feed the heaters of a vacuum tube on a guitar amp, AC or DC? With the same transformer, is it possible to change between AC and DC supply for the heaters?
user22230
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Why are thermionic valve/tube heaters generally designed to be 6.3 V?

Why are the heaters generally 6.3 V (or multiples thereof)? Does it make for an easy transformer winding ratio when used in countries with 120 VAC or 240 VAC mains? They often pull quite significant current, and as there's generally a higher voltage…
Colin
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Thyratrons: How they work, what they are used for, and how to read their datasheets

I recently ran into an interesting device called a thyratron. I have a basic understanding of thyratrons as gas filled vacuum tubes. I understand that they can switch large amounts of currents and voltages over short time spans very accurately.…
Alex Eftimiades
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Why is a pentode tube more power efficient than a triode tube?

As title. I read some article and it says something like this: Tetrode was invented to reduce grid-plate capacitance. Pentode was invented to reduce secondary emission. I also heard that a pentode has greater power efficiency than a triode. I…
Moses
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Troubleshooting Hum in a Tube Guitar Amp

I have a Fender Deluxe Reverb Reissue guitar amplifier that hums whenever I turn on the reverb. It sounds like loud 60 cycle hum. The reverb effect is still applied, but is accompanied by the hum. Here's what I've observed about the hum: -It only…
Avid Pro Tool
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UHF Tesla coil powered by low voltage?

I want to know if it is possible to use a 2.4 GHz magnetron as a oscillator for a Tesla coil circuit. The idea is to use a oscillating relay-driven step up transformer (12 V to 10 kV) and then charge a capacitor bank up, just to smooth the DC…
South African Railfan
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Open-air electron tube

So, I know that vacuum tubes only work because they're, well, a vacuum, and gas-filled tubes have a hysteretic effect relating to gas ionization. My question, however, is this: Would an open-air 'tube' be a viable device in any situation? Of…
Hearth
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What is a Reacto Tester unit and are there any projects in which I can use it?

I was given an old piece of electronics. It is a Reacto Tester made by Antronic Corp from Chicago. After a quick glance at the manual it seems that its a tester for tube display units such as television (color and black). I am wondering if there is…
KingsInnerSoul
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Obtaining 4-4.2V rail from 5V output of LM7805 voltage regulator

I'm creating a numitron clock with 4xIV-9 tubes (seven-segment filament displays) and have decided to illuminate them using shift registers controlled by an arduino. Each segment takes a voltage of 4-4.2V and around 17-20mA of current. My voltage I…
Daniel Bod
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12 - 330v boost converter

I recently bought a G10/241E tube and I need a power supply for it. There are no designs of a 330V DC power supply and no buck-boost converters would work with such voltage. The datasheet and example circuit: Unidirectional Cold-Cathode Gas-Filled…
Velociraptor
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Replacement for tube-based trigger switch (Thyratron) in high-voltage supply

A now-deleted question asked whether it's possible to replace the trigger in a specific application (laser supply, source here): and other things. For me, it boils down to a single, less application-specific question: why is it hard to replace…
Marcus Müller
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Required transformer voltage for voltage regulator tubes in series

First of all some small context: I am attempting to design and build a clock with old electricial components, without silicon components. This question is about the power supply circuit. Note that I have no degree in electronics whatsoever, I have…
user326520
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How does the feedback in this tube amp output driver work?

The figure shows the output stage of a vacuum-tube audio amplifier. While I was reading through this schematic, I noticed there is a some kind of feedback associated with R24. However, this feedback seems positive feedback to me. The right side of…
Emm386
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How do glass tube fuses work?

This may be the an unspeakably stupid question for an electrical/computer engineering student to ask, but I ran across a few parts I didn't recognize (which, after some research, I found out were glass tube fuses and automotive fuses), and they made…
root
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