Some useful Programs for Download
1 Smith.zip.
This is a program to produce a Smith Chart and help you with
calculations on matching and filtering, and coax stubs. There
have been many articles on the use of Smith charts. Although many
would regard them as outdated in the age of the computer, the
visual display of impedance (or admittance if you prefer ) helps
a lot to give a grasp of a problem. This program was sent to me
over packet and was is Basicode (which shows its age!!) a sort of
Esperanto of Basic, which was used a lot in Europe in the 1980s.
I have made a slight alteration to introduce a little colour and
compiled it with QuickBasic 4.5. It will run in a DOS window in
Win9x (I have only 95 to try it on.)
Click here to download Smith.zip
2 ACN.zip
ACN is a program which will perform an AC analysis on an active
or passive network. It was developed from an idea published for
use with an HP printing desk calculator in the early 1980s. The
original Basic translation I did (from HPL) was rewritten in
Pascal to speed it up and extend the number of nodes it handled
and substantially embellished with coloured graphics by Gordon
Hathaway, a collegue of mine at BTRL. The program has been placed
in the Public Domain, and may be used freely. It may not be
reverse engineered or the programmers name removed. It does not
contain any screen capture routines for the graphs. Gordon's idea
was that everyone has their own favourite screen grabber. If all
else fails a CTRL-PrtSc will copy the graph to the clipboard
which may then be pasted into Paint or PaintShopPro. The program
requires a 486 minimum or a 386DX and will run under DOS. It runs
in a DOS window in Win9x. There is a fairly extensive help
screen, but it may be that those who have not been invoved in the
specification of transistor parameters may find the entry to the
net table a little confusing. I have added some more notes on
this topic, which may be downloaded as a separate file. In the
mean time if you can get hold of a demo copy of Electronic
Workbench, or one of the other simulators, you can probably copy
the appropriate op-amp and transistor parameters from there. The
example files (.CKT) are mainly filters, and can be loaded from
within the program. There are many more colourful analysis
programs which include schematic circuit entry, but I think this
is good for a freebie, though it is all keyboard driven (which
shows its age). Filters built and swept (in particular the RTTY
filter ) matched the output very closely which gives me a lot of
confidence. Gordon did use it professionally for video amp and
equaliser work I believe.
Copyright for this code remains the property of Gordon Hathaway.
Click here to download ACN.zip
Click here for some ancilliary notes on active device modelling in ACN
3 Resonate.zip
Resonate.zip is a simple Windows utility to calculate the
resonant frequency of a capacitor and inductor. Loads of those
around, I hear you say.....but just try this one! I allows you to
nudge the capacitor and inductor up and down in value with either
big or small steps, whilst continually calculating the resonant
frequency. This means you can find the value of capacity that
will resonate a 1.17mH coil at 127.6kHz.....if you so
desire....by just 'nudging' the capacity until the resonant
frequency reads as desired. A bit like a One-Arm Bandit (....Ah
signs of a mis-spent youth) It will also calculate the reactance
of the capacitor at the resonant frequency. It has one more
little gem.....if you clear the inductance box you can type in a
frequency and capacitance and click calculate for the reactance.
If you require the reactance of an inductor, type in the inductor
value, resonate it at the desired frequency by 'nudging' the
capacity value. Then the inductive reactance is equal to the
capacitive reactance. Likewise if you have exact values in the
boxes click the "Calculate" button. Because it is a
relatively small program you can keep it minimised and pull it up
over other applications, like the Smith Chart, for 'user
friendly' calculations. Now the warning....it is written for
Win95 but I have reports it loads and runs OK on '98, 2000, ME
and XP. Please let me know if it will not run, as I only have '95
to test it on. It was written as a learning exercise so it does
not have any entry trapping, if you type in something stupid it
will probably fold up. The .EXE file is just 23kB long.
Click here to download Resonate.zip
5. Excel Spreadsheet for CV valve number conversion to
commercial equivalents and the reverse
The majority of the sheet with the data is 'protected' there are
two boxes on line '2' where you may type the number of the CV
type you wish to find the commercial equivalent of (or the
reverse). The VLOOKUP function will find the first occurance, so
if you are looking for 6146 for example, if you cursor down the
list you will find several other entries below the selected one.
Click here to download CVconv.zip (abt 85k)