Help Needed on Cathode Ray Tubes for TVs

In summary, the conversation discusses the process of electron emission in a TV set and how the heating filament replenishes its stock of electrons from an AC supply. It also touches on the potential difference between the cathode and anode and where it comes from, as well as the role of a high voltage power supply in accelerating the electrons. The conversation ends with a request for clarification and an email address for further communication.
  • #1
aku2590
3
0
Is there anybody out there that can help me??

Ok in a TV set, the electrons that are emitted come from the heating filament. Now as i read on this site...the heating filament replenishes its stock of electrons from an AC supply. I understand that bit. So there is an AC supply of electrons to the heating filament.

now comes the cathode and anode that have a potential difference across them. where do they get their potential difference from? Is there a separate circuit? Because they need a very large potential difference and as i read somewhere previously, the heating filament only needs about 6.3V. So i don't understand how if i had to draw a circuit diagram, i would do it. Then to confuse me more, we only plug in one adapter when plugging in a tv. So the current from this adapter, is it split??

I get the basic stuff of how the electrons are emitted, then accelerated, then their kinetic energy carries them past the anodes to the surface. But its just the earlier part as to how the circuit itself operates. Id really appreciate if someone could help me out on this...my email is aku2590@hotmail.com if ud like to write to that...
Thanx alot...
 
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  • #2
Yes, there is a high voltage power supply which provides the accelerating potential. Not sure what the moderen tubes run at but historically were somewhere around 15kV, possibly as high as 25kV.
 
  • #3



Hello there,

I understand your confusion about the circuit operation in cathode ray tubes (CRTs) for TVs. Let me try to explain it to you.

Firstly, yes, there is a separate circuit for the cathode and anode in CRTs. The heating filament is connected to one end of the cathode, while the other end of the cathode is connected to the anode. This creates a potential difference between the cathode and the anode, which is necessary for the electrons to be emitted and accelerated.

The potential difference between the cathode and anode is created by the high voltage transformer in the TV. This transformer takes the 6.3V from the heating filament and steps it up to several thousand volts, enough to create the necessary potential difference for the CRT to function.

As for the adapter, it provides the necessary power for the entire TV, including the high voltage transformer. The current is not split, but rather the transformer uses the 6.3V from the heating filament and transforms it into the higher voltage needed for the CRT.

I hope this helps clarify things for you. If you have any further questions, please feel free to reach out to me. Best of luck with your TV project!
 

1. What are cathode ray tubes (CRTs) used for in TVs?

Cathode ray tubes are used as the display screen in traditional tube televisions. They work by using an electron gun to shoot a beam of electrons onto a phosphor-coated screen, creating the images that we see on TV.

2. How do CRTs differ from newer TV technologies like LCD and LED?

CRTs use a completely different technology than LCD and LED TVs. While CRTs use an electron beam to create images, LCD and LED TVs use liquid crystals and light-emitting diodes to produce images. This results in different display qualities and sizes.

3. Can CRTs be repaired if there is an issue with the display?

Yes, CRTs can be repaired if there is a problem with the display. However, the cost of repair may not be worth it as CRT technology is becoming obsolete and replacement parts may be difficult to find.

4. Are there any safety concerns with CRTs?

Yes, there are safety concerns with CRTs as they use high-voltage electricity to create images. It is important to handle CRTs with caution and follow proper safety procedures when working with them.

5. Are CRTs still being produced and used in TVs today?

No, CRTs are no longer being produced and are less commonly used in TVs today. They have been largely replaced by newer technologies such as LCD and LED, which offer better display quality and are more energy efficient.

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