[Boatanchors] Funny Craig's list Ad for Oscilloscope

[J. Forster]

That's not so clear. I don't know the max accelerating voltage on those
tubes but I've never seen one run much higher tha 4 - 5 KV. This means the
electron beam is relatively slow.

You cannot deflect the beam much if the time taken for the beam to travel
the length of the deflection plates is greater than the half-period of the
signal. The beam just wiggles, not bends.

-John

============


> The maximum display rate that a typical CRT can support is orders
> of magnitude
> higher than what a non-distributed hollow-state 'scope amplifier can
> manage.
>
> The monitor scopes used for observing modulation of AM transmitters, etc,
> since the 1930's are capable of operation up to 10m with no problem, since
> the plates are driven directly with (a sample of) the RF; no amplification
> needed.
>
> The capacitance between deflection electrode pairs in a 5UP1 (I don't have
> a data sheet for the 5BP1) is only 2.5pF. If you used one of the old Tek
> scope
> amplifier designs (with peaking coils, etc) you could probably build a
> scope
> that would handle 25MHz.
>
> 73, ian K3IMW
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