Some useful Programs for Download
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 Although many would regard them as outdated in the age of the computer, the visual display of impedance (or admittance if you prefer ) helps a lot to give a grasp of a problem.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
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
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)