[Ktechlab-devel] My ktechlab modifications

[thomas at tgohome.com]

Hi,

I'm back again.

After a bit of getting used to patch/diff - it's the first time I've
really got used to it - I made a patch file. See here:
  http://files.getdropbox.com/u/1134084/ktechlab-over-rate-additions-plus-more-by-Tom-Oldbury.patch

Hopefully I did it right - please can someone try it out on a copy of
current SVN.

Now to work on more stuff.

Tom

> I'm more of an analog kinda guy, I don't really deal that much with
> digital circuits yet - but I'm still learning. Could the glitch be
> prevented by making inputs and outputs directional (inputs can only take
> in signals, outputs can only put signals in.) I assume that you've thought
> of this already and there's some very good reason it isn't done...
>
> Anyway, I will be creating a patch based on current SVN soon.
>
> Quick status check. I've added over-rates for resistors now. Resistors
> also display the power they're dissipating. See screenshot:
>   http://files.getdropbox.com/u/1134084/ResistorOverRatePlusPower.png
>
> (In the picture the resistor is 1/2W, 350V max., so it would normally be
> burning up and destroying itself.)
>
> I was thinking of doing some of the following:
>  - NTC/PTC resistors. These resistors vary resistance with temperature.
> The resistors can be specifically designed to warm up and reduce/increase
> resistance. For example, in some CRT TVs, they are used to control the
> CRT degauss coil - as the TV starts up the resistor is cool, and at a low
> resistane, and the coil degausses the TV. Then when the resistor's
> temperature increases the coil reduces in power over a few seconds. A bit
> of a speciality item, but would be a very neat addition.
>  - Variable resistors with:
>    - Log/antilog/linear scale.
>    - Power dissipation/voltage limits, identical to fixed resistors.
>    - Update value next to resistor (maybe) depending on slider value. Or
> put another value next to slider.
>  - Signal generator/voltage signal modifications:
>    - If possible, add other types of wave: sawtooth (a triangle wave with
> 100% rise 0% fall), triangle, square and white noise.
>    - Symmetry, for square and triangle waves.
>  - For all voltage sources: warn if excess current/short circuit.
>  - Allow plotting of things like power dissipation through a resistor,
> charge in a capacitor, joules in a capacitor, etc.
>  - Transformers.
>  - Relays. Model as an inductor, so we get back EMF. Switch is controlled
> by current through inductor.
>  - Thyristors, TRIACS, and other needed semiconductor devices.
>  - For transistors, back-EMF shows warning.
>
> That's a long list of possible things to do, but I'd really like to
> improve KTechLab because the other software I've come across is either
> commercial  /not open-source, or Windows-only, or slow / non-functional in
> Wine or has significant analog bugs that affect me. It's also a first big,
> open-source project that I've ever worked on, and great C(++) experience.
>
> I have noticed that in my SVN version LEDs and diodes do not work. Is this
> (or was this) a problem with SVN a bit back?
>
> Tom
>
>> thomas at tgohome.com wrote:
>>> Hi... Again,
>>>
>>> I have made some more tweaks... I've added capacitor over-rates, and
>>> I've
>>> also fixed many NPN transistor over-rate bugs. I added maximum power
>>> dissipation for transistors as well (however, I'd like someone else to
>>> review that I'm doing it correctly)
>>
>>> One thing I added to capacitors (only fixed capacitors at the moment,
>>> maybe variable caps soon) was a polar setting, and a maximum working
>>> voltage setting. If the capacitor is polar, then it cannot tolerate
>>> more
>>> than 2.5 volts backward. (This might be a setting later, but at the
>>> moment
>>> it's fixed.) If working voltage is exceeded, or the capacitor is run in
>>> reverse (when it is polar) an over-rate warning is shown. I also added
>>> charge (coulombs), energy (joules) and volts to the tooltip for the
>>> capacitor.
>>
>> You are obviously far more capable of working with the GUI and front end
>> than I am.
>>
>> My own changes had been focused on refactoring the code such that it was
>> more reliable and more accurate.
>>
>> Currently there are massive problems with most nonlinear components. =(
>>
>> My most recent fix involved the Logic out, I think I did a half-way
>> decent job of modeling the internal impedance of the port.
>>
>> One kinda cool thing ktechlab does now is with SR flip-flops, if you
>> connect the output of a SR to an external voltage source and you can
>> overpower the output impedance, you can force the part to change state!
>> =P This is because the SR flipflop is basically two NOR gates, the
>> output of one being one of the inputs of the other, so if you overpower
>> that output (probably destroying the part!), you can cause it to change
>> states. =P
>>
>> The code works because the implementation of SR flipflop is currently
>> stateless, it uses nothing other than the states of its pins to
>> function. Because LogicOut is a subclass of LogicIn, the output pins
>> have all the functionality of input pins! Furthermore, I consolidated
>> all state information for the pin down to a single state variable. So
>> when you overpower the output, you can force it to change state which
>> then triggers the normal cascade of events... =P
>>
>> It might also be useful to implement T-flip-flops at some point to
>> simplify some other code, such as my DAC demo.
>>
>>
>> --
>> New president: Here we go again...
>> Chemistry.com: A total rip-off.
>> Powers are not rights.
>>
>>
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