Question about home CRT experiment

[yoemeuunito]

I'm looking to setup a homemade CRT experiment, for two purposes the first is of course the standard tests for observation but the second and main reason why I'm looking to do this I will now explain: From what I have managed to assertain Magnets are able to affect the electrons passing in the tube, and what from that it is my understanding that the electrons should be capable of inducing an electric current within a copper coil that is wrapped around the head of the tube.

 

I am here to ask for the opinion and knowledge of the community members in regards to this, and whether or not this is an accurate assumption to make. I have far too many projects, most of which I'm sure will never see completion, as such I do not wish to waste my time on pointless endeavors. If it is possible to produce a current using this method I would very much appreciate it if someone could let me know.

 

A small note: I've had to join this forum to ask about this kind of thing because I've unfortunately been unsuccessful in finding any information on this specific topic. If any more information is required please ask.

[Strange]

From what I have managed to assertain Magnets are able to affect the electrons passing in the tube,

 

Yes, magnets will exert a force on the electrons (because they are moving). This is how the electron beam is made to scan the screen in a CRT monitor.

 

and what from that it is my understanding that the electrons should be capable of inducing an electric current within a copper coil that is wrapped around the head of the tube.

 

Only changes in the electron beam could generate a current in the coil. You would also need to work out, roughly, what the magnitude of this would be and whether it would be detectable. My guess is it would be pretty small, but I don't really know.

[studiot]

The first thing to know is that there are two types of CRT and to find out which you will be using.

 

Both types generate a beam of electrons emitted by the cathode and accelerated and through the anode.

On passing through they impact on the phosphor of the screen whence light is emitted.

To prevent build up the screen has an earthing layer.

 

This electron beam constitutes an electric current.

 

It is this electric current that needs to 'thread' any conducting pickup loop to generate current, and yes, if it does so it will generate current in accordance with Faradays's's laws.

 

So much for the similarity of the types of CRT. Now for the differences.

 

The electron beam is not arandom broad brush spray, it is focused into a tight beam that strikes as small a spot on the screen as possible.

This strike spot is moved about on the screen to create the wanted image.

The difference lies in the way the beam is focused and moved about (deflected).

 

Two methods are available, magnetic and electrostatic.

Magnetic methods are used in CRTs designed for television and computer screens.

Such screens are designed to display what is known as a raster.

In a raster the beam is scanned in regular lines abckwards and forwards across the screen, covering the screen in a series of lines.

 

Electrostatic methods are used in CRTs designed for oscilloscopes, radar and echo sounders and similar instruments.

The beam here is used as an electronic pen and 'writes' (traces out) a continuous line on the screen of the desired image, going where is will (needs to) in order to achieve this.

 

Two comments about safety need also to be made.

CRT's employ the use of (very) high voltages which can result in serious accidents if not properly treated

CRT action generates x rays which can be a hazard if allowed to spread into the surroundings.

 

Does this help?

Edited February 3, 2016 by studiot