Speed of O-scope electrons - Electronic Circuits Projects Diagrams Free

Michael Cotter · 18th November 2002, 03:46 PM

I have an old HP O-scope out of which I am making a JJ Thompson charge to mass ratio experiment. Does anyone know about how fast the electrons are moving when they leave the electron gun?

**kinjalgp** · 18th November 2002, 06:49 PM

Hi, normally speed of electrons is same as that of photons i.e. light and it is 3x10E8 m/S.

pebe · 18th November 2002, 07:58 PM

I don't know about the HP O scope, but if it uses a normal, electrostatically deflected, oscilloscope tube, the electrons speed will travel at nowhere near the speed of light.

The usual arrangement in the gun is that electrons leave the cathode relatively slowly and are attracted toward, and accelerated by, the anode and controlled by the grid in the same manner as a thermionic valve (tube). There are additional anodes which further accelerate and focus the beam.

In some 'scopes, there is a final anode after the deflection plates. This has the advantage that deflection is done when the electrons are moving relatively slowly and deflection is easier, then finally accelerated to max to hit the screen.

**kinjalgp** · 19th November 2002, 05:23 AM

Yes, in normal case speed of Electrons is that of light but you can control their speed. I was talking about the normal speed and not in O-Scope.
Thanks for pointing pebe

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18th November 2002, 03:46 PM	#1
Michael Cotter	Speed of O-scope electrons I have an old HP O-scope out of which I am making a JJ Thompson charge to mass ratio experiment. Does anyone know about how fast the electrons are moving when they leave the electron gun?

18th November 2002, 06:49 PM	#2
kinjalgp	Hi, normally speed of electrons is same as that of photons i.e. light and it is 3x10E8 m/S. __________________ "There is no way to peace, peace is the way!"

18th November 2002, 07:58 PM	#3
pebe	electron speed I don't know about the HP O scope, but if it uses a normal, electrostatically deflected, oscilloscope tube, the electrons speed will travel at nowhere near the speed of light. The usual arrangement in the gun is that electrons leave the cathode relatively slowly and are attracted toward, and accelerated by, the anode and controlled by the grid in the same manner as a thermionic valve (tube). There are additional anodes which further accelerate and focus the beam. In some 'scopes, there is a final anode after the deflection plates. This has the advantage that deflection is done when the electrons are moving relatively slowly and deflection is easier, then finally accelerated to max to hit the screen.

19th November 2002, 05:23 AM	#4
kinjalgp	Yes, in normal case speed of Electrons is that of light but you can control their speed. I was talking about the normal speed and not in O-Scope. Thanks for pointing pebe __________________ "There is no way to peace, peace is the way!"