[GreenKeys] LTSpice

[Chris Elmquist]

This is a great discussion guys.   Is there a reason (other than
not being authentic or period correct) that you wouldn't use a TVS diode
for this problem today?

Chris N0JCF

On Sunday (07/21/2013 at 10:24AM -0500), Jeffrey D Angus wrote:
> On 7/21/2013 9:50 AM, Ralph Mowery wrote:
> >In it was a mention of the snubbing circuit and that it would contribute
> >to the marking bias.
> >
> >I just wonder that while adjusting the values to solve one problem
> >if maybe
> >another problem might be created ?
> >
> >I don't know enough about computer simulations to say if it is
> >possiable to
> >look at how much distortion may be caused by differant values of the
> >snubbing circuit or if is even enough to worry about.
> In a word, yes. Having the simulator running is a great exercise in
> "what does
> this have an effect on?"
> 
> Mostly the snubber affects what happens on the transition from Mark to
> Space. And quite frankly, unless you've put an enormous value of C in the
> snubber, the Selector magnet is going to pretty much going to let go when
> the loop opens up.
> 
> However, with too small a value, the over shoot and ringing issues are going
> to beat the hell out of the loop keying circuit.
> 
> What does make a difference, is the open circuit voltage. Dropping the loop
> supply from 120 to 60 volts, and adjusting the current limiting
> resistor back
> to 60 mA, really slows down the rise time on the selector magnet current.
> 
> Jeff-1.0
> wa6fwi

-- 
Chris Elmquist