a few home-made engineering programs

On a sunny day (Fri, 10 Sep 2021 08:41:52 -0700) it happened snipped-for-privacy@highlandsniptechnology.com wrote in snipped-for-privacy@4ax.com:

Nice, for unit conversion I use Linux 'units' ~# units Currency exchange rates from FloatRates (USD base) on 2018-10-20

2916 units, 92 prefixes, 107 nonlinear units

You have: 1 F You want: uF * 1000000 / 1e-06 You have: 1 pint You want: liters * 0.47317647 / 2.1133764 You have: 1 gallon You want: pints * 8 / 0.125 You have:

I can run U and type

2ft

or

27um

and see all the conversions.

On a sunny day (Fri, 10 Sep 2021 09:08:00 -0700) it happened snipped-for-privacy@highlandsniptechnology.com wrote in snipped-for-privacy@4ax.com:

Sure, 'units' can do that too: You have: 3 feet You want: cm * 91.44 / 0.010936133 You have: 22 uF You want: F * 2.2e-05 / 45454.545 You have: 12 km You want: miles * 7.4564543 / 0.134112

This is a pretty good web-based LC filter design tool, I've used it a number of times for real stuff and the performance checks out. Does most of the common filter types and typologies.

I've tried several freeware stand-alone apps that are buggy or crash-y or both

fredag den 10. september 2021 kl. 18.02.54 UTC+2 skrev Jan Panteltje:

google also does units

Looks nice, but I think I broke it by specifying a filter that's 50 ohms on one end and 10K on the other.

I often design filters that are, say, 50 ohms on one end and high or infinite on the other.

What do they do?

Cheers

Phil Hobbs

There's a text file in that folder. Here it is:

JL's home-made engineering programs Sep 10 2021

BESSIE7 designs LC Bessel filters

INSULT calculates thermal conductivity

LC7 does LC resonance calcs

LINELC calcs L and C of a transmission line

NOISE calculates Johnson and shot noise (if a part has it)

NORMA normalizes an LC filter prototype

SCUT is a serial interface terminal thing

U is a units converter

All are Windows console apps coded in PowerBasic.

I didn't include one of my faves, RUGRAT.EXE. Given a list of resistors, it finds pairs that make a given ratio. It does require a candidate list in our format.

ResCAD.exe has it's own built-in list of standard values and tolerances.

RUGRAT finds ratios using parts that we have in stock now.

We also do a lot of feeder minimization, which further restricts what parts we can use. I can look at the RUGRAT report and, for example, find a good ratio and use one of the values somewhere else on the board, maybe in another ratio.

Yes, yours is a definite purpose program. ResCAD is for general purpose.