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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 24th Apr 2018, 12:05 am   #21
Argus25
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Default Re: ‘scope query: instantaneous , one-shot trigger and hold ?

....I could have added that when CRT's became obsolete for scopes so did the requirement for a linear sawtooth deflection wave. The problem then became that of a digital counter to clock along to the next flat screen pixel at a controlled rate.

Puckle's original time base circuit from the early 1930's got called the "Cossor Hard Valve Timebase" since it used the usual high vacuum valves, versus gas filled (soft) discharge tubes. It was used in scopes like the Cossor 339A.
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Old 24th Apr 2018, 6:00 am   #22
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Default Re: ‘scope query: instantaneous , one-shot trigger and hold ?

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I'd never heard of Howard Vollum -- is he something of an under-celebrated figure?
Depends who you ask! Relatively few people know or care about the history of oscilloscopes development, but the company he co-founded went on to be the world leader in the field for several decades, so he has quite a legacy.

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Old 24th Apr 2018, 6:58 am   #23
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Default Re: ‘scope query: instantaneous , one-shot trigger and hold ?

Howard Vollum is quite well known. His triggered timebase revolutionised oscilloscopes.

He originally took the idea to Bill Hewlett and Dave Packard, but they were too busy with microwave test gear and they advised him to start up his own firm, it was clearly a great invention. I believe he got some help.

So despite all the supposed Tek/HP wars, the founders were on friendly terms.

You can't really drive a scope until you understand the difference between 'norm' and 'auto' triggering and all the trigger options. After that comes the effect of the 'holdoff' control and then delayed timebases.

It's easy once you've built up a mental model of what these things do, but before that it can appear confusing.

Students usually have to use reasonably comprehensive scopes at university and so get familiar. Next rung up on the scary ladder is the spectrum analyser, while 90% of the raison d'etre of network analysers is for inducing absolute terror in students. Meanwhile, outside in the real world, they eventually have to become comfortable with all of them.

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Old 24th Apr 2018, 7:52 am   #24
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Default Re: ‘scope query: instantaneous , one-shot trigger and hold ?

The delay Timebase, in conjunction with H & V sync separators really revolutionised the examination of analog video signals, as each field, or sections of it, can be easily be examined. Unfortunately most Tek scopes (even the 2465B and the earlier 464 etc ) although having the delay Timebase only had the video sync separators as an option. Hitachi though had H & V sync separators in most of their high end scopes. A very good portable Hitachi scope for this and other reasons is the V509 which is excellent for analog television work.
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Old 24th Apr 2018, 11:06 am   #25
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Default Re: ‘scope query: instantaneous , one-shot trigger and hold ?

Looking at an analogue TV signal with a dual timebase scope could be quite educational. You can scroll through line by line and examine detail in each line. Some lines have VITS - Video Inserted Test Signals.... stepped ramps, colour bursts, 2T pulses and all sorts of stuff.

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Old 24th Apr 2018, 12:50 pm   #26
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Default Re: ‘scope query: instantaneous , one-shot trigger and hold ?

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You can't really drive a scope until you understand the difference between 'norm' and 'auto' triggering and all the trigger options. After that comes the effect of the 'holdoff' control and then delayed timebases.
Indeed, yes! The delayed timebase is awesome, whether delayed then triggered, or delayed free running, both can be invaluable for close examination of part of a waveform.

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...except that with complimentary transistors yet another generation of designs became possible that were not possible with valves.
Ah yes, the PNP valve, the holy grail of thermionic valve technology! All we need is a material which emits positrons when heated...
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Old 24th Apr 2018, 1:07 pm   #27
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Default Re: ‘scope query: instantaneous , one-shot trigger and hold ?

Once you have a positron emitter you can form them into a beam and we all know the terrible trouble that ensues once someone makes a positronic ray device and all the bad acting which follows (EG: 'Barbarella' it even got Marcel Marceau into a speaking part).

It's probably as well the little beggars play hard to find.

I'm beginning to wonder what the OP is up to now... lots of amps, ultra fast risetimes... hmm... he's not trying to make a positronic weapon do you suppose? ...things travelling "Faster than the electricity meter at CERN"

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Old 24th Apr 2018, 2:12 pm   #28
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Default Re: ‘scope query: instantaneous , one-shot trigger and hold ?

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I'm beginning to wonder what the OP is up to now... lots of amps, ultra fast risetimes... hmm... he's not trying to make a positronic weapon do you suppose? ..

Hands up, David! You caught me!
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Old 24th Apr 2018, 2:36 pm   #29
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Default Re: ‘scope query: instantaneous , one-shot trigger and hold ?

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Once you have a positron emitter you can form them into a beam ...
I suppose you'd call that DC (Dirac Current)
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Old 24th Apr 2018, 2:40 pm   #30
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Default Re: ‘scope query: instantaneous , one-shot trigger and hold ?

As long as the irresistible force isn't pointed at an immovable object.........
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Old 24th Apr 2018, 7:32 pm   #31
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Default Re: ‘scope query: instantaneous , one-shot trigger and hold ?

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I suppose you'd call that DC (Dirac Current)

I notice your use of Bra-kets there!
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Old 24th Apr 2018, 8:37 pm   #32
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I notice your use of Bra-kets there!
Very good!
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Old 25th Apr 2018, 11:59 am   #33
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Default Re: ‘scope query: instantaneous , one-shot trigger and hold ?

I had to Google that...
...I wish I hadn't
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