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Early switcher with schematic

Started by bitrex February 18, 2019
<http://www.righto.com/2018/09/glowing-mercury-thyratrons-inside-1940s.html>

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...
On 19.2.19 02:43, bitrex wrote:
> <http://www.righto.com/2018/09/glowing-mercury-thyratrons-inside-1940s.html> > > > 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...
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. -- -TV
On Mon, 18 Feb 2019 19:43:11 -0500, bitrex <user@example.net> wrote:

><http://www.righto.com/2018/09/glowing-mercury-thyratrons-inside-1940s.html>
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 components. 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.
>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...
upsidedown@downunder.com wrote in
news:qp2o6ehqtrqg3e9vk54nfb3eoa0vj18h6e@4ax.com: 

> On Mon, 18 Feb 2019 19:43:11 -0500, bitrex <user@example.net> > wrote: > >><http://www.righto.com/2018/09/glowing-mercury-thyratrons-inside-
19
>>40s.html> > > 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 components. > > 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. >
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.
>>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... > >
On 02/19/2019 10:56 AM, DecadentLinuxUserNumeroUno@decadence.org wrote:
> upsidedown@downunder.com wrote in > news:qp2o6ehqtrqg3e9vk54nfb3eoa0vj18h6e@4ax.com: > >> On Mon, 18 Feb 2019 19:43:11 -0500, bitrex <user@example.net> >> wrote: >> >>> <http://www.righto.com/2018/09/glowing-mercury-thyratrons-inside- > 19 >>> 40s.html> >> >> 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 components. >> >> 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. >> > > 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.
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.
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.

Tim

-- 
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/

"bitrex" <user@example.net> wrote in message 
news:AiIaE.604$rQ7.391@fx09.iad...
> <http://www.righto.com/2018/09/glowing-mercury-thyratrons-inside-1940s.html> > > 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...