[GreenKeys] LTSpice

[Ralph Mowery]

Thanks for the graphs.  There sure is a big differance in the two curves.

The one with the 470 resistor looks like the curve for control circuits.  I 
worked in instruments in a plant.

 They used thousands of PID control loops.  If you are not familiar with it, 
think of trying to control the temperature of a pot that holds about 1000 
gallons with stuff comming in and going out all the time.  If there was an 
upset, the controlers would open valves to adjust the flow and temperature.

I don't recall the values of the magnets on the old teletype machines but 
think they are about 2 or 4 henrys each or for each pair.

de ku4pt



----- Original Message ----- 
From: "Jeffrey D Angus" <jdangus at att.net>
To: <greenkeys at mailman.qth.net>
Sent: Friday, July 19, 2013 4:03 PM
Subject: Re: [GreenKeys] LTSpice


> On 7/19/2013 11:00 AM, Ralph Mowery wrote:
>> What hapens when you plug in the values of .1 uf and 470 ohms ?
>> That is what Hoff used in his design from about 40 years ago.
>> That is for a loop voltage of around 150 volts and 60 ma.
> It depends on a lot of things. including the actual inductance of
> the selector magnet. These two charts were based on 2 Henries.
> Then only changing the capacitor from a 0.1 uF to a 0.47 uF.
>
> You can see the difference in the amount of overshoot and ringing.
>
> You may need an .xpf document viewer to see these files.
>
> Jeff-1.0
> wa6fwi
>
>
>