Early switcher with schematic

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I've been looking for an LTSpice model for a thyratron like the 2D21 for  
a while, anyone have one? probably not too difficult to DIY a behavioral  
model I guess...

Re: Early switcher with schematic
On 19.2.19 02:43, bitrex wrote:
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Actually, it is not a switcher, as we know them by now. It is
rather a phase-angle controlled regulated DC supply. There are
plenty of modern analogs to it using SCR's.



Re: Early switcher with schematic

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Why would a Teletype need such complex power supply ?

One Teletype (look-a-like) machine was used as a 1960's minicomputer
console with 20 mA current loop interface. It had totally 6
semiconductors, four rectifier diodes, and a TO-3 power transistor and
a zener diode in the 20 mA constant current loop current generator.
Everything else was done by mechanical and electromechanical

Before semiconductors, this could have been done with a double diode
as full wave rectifier and a triode as a constant current source (or
just a resistor from a sufficiently high voltage).

That regulated thyratron supply most likely powered the radio
equipment in a RTTY station.

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Re: Early switcher with schematic
snipped-for-privacy@downunder.com wrote in

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  Did you even look at the entire page?  It is an impressive  
examination/collection he has made.  Anyway, the switcher's  
schematic is there, and you can see its output traces too.  I doubt  
it would fire a transmitter, but that too was my first thought until  
I looked over the items on the page.  Maybe it was so it would  
operate in different places with different power systems.

Look at the different transmission systems of the time for  
transmitting digital data.  Both over wire and OTA.

  The teletype machine is where the term baud rate came from.

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Re: Early switcher with schematic
On 02/19/2019 10:56 AM, snipped-for-privacy@decadence.org wrote:
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Yeah it looks like the function was more towards "line regulation" than  
load regulation. Designed for military service wherever it needed to be  
in the world, at a time when power line voltages and freqs were  
nonstandardized/unreliable. What AC power we got today. Who knows could  
be anything.

Re: Early switcher with schematic
Very much doubt you'll find a model, but if you must, a JFET strapped to an  
SCR model wouldn't be embarassingly far off.


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Electrical Engineering Consultation and Design
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