After a 2-week hard work, (with large breaks in between :), this program has started to work... quite well. What does it do? It measures piecesÖ like any other multimeterÖ Why have I done it? Well, I believe this is a much cheaper version of a multimeter, which measures capacities, inductances and resistances. It should become useful to any amateur electrician (or to a poor one), who has a computer (486 DX4, 16Mb minimum requirements) and Windows 9x.
|In order to make the program work, you will need Windows 9x, a Full duplex sound card with already installed drivers, 2 jack stereo couplings with 1-2 meters wires and a resistance. Download this program (100Ko).|
|This is the way you must make the connections. Sticking some wires and a resistance shouldnít be too difficult. You will choose one channel from the speaker exit of the sound card (or you will join both channels using resistances of minimum 8 Ohm and further on the channels will be connected between the resistances), you will make all the other marked connections (to LineIn) and... GO!|
About how this program works (although I doubt that anyone should be interested)...
How does the program measure the pieces?
Resistances : the difference between the intensity of the signal between the channels.
Inductances/capacitors : the difference between the intensity of the signal between the channels and, as a plus, the phase difference between them.
What is the difference between the 2 types of measurements? The first uses only one frequency (the one in the left) and is based only on the phase difference. The second one uses both frequencies and the result is provided by a system of 2 equations with 2 unknowns ... gotcha, ha? LOL The 2 frequencies shouldnít be too close (under 10%) or too different (over 200%). If they are identical (I havenít even tried it, believe me?), the second method canít work. The second method has one more advantage: it can make the difference between inductances and capacities, and this is why itís appropriate in these cases. As for the resistances, it doesnít work too well.
As Iíve also written in the program, if you like and use it, please send me an email, so that I can see what you think of it (is it too expensive? :). Enjoy using it! Oh! Iíve almost forgotten! Donít try the program on the speakers! You may not like the sounds it produces!
How does it work on my computer ? Well, on my sound card (YMF 724) I measure in a continuous scale, from 0.22 uF to over 1000 uF, with the frequencies set at 100/1000 and 20 Ohm serial resistance. If you want to measure small condensers (like 0.01 uF), try on bigger serial resistance (but not bigger than 1000 Ohm) and larger frequencies (but not larger than 1000 Hz). The resistances in a scale from 1 Ohm to some 10kOhm, again with the serial resistance of 20 Ohm. About the coils... not quite good news... the program works only on paper. What does that mean? I donít have any standard inductances in order to check if it works accurately. However, by the way I designed the program, it should work. Maybe one of the users will let me know how the program works with the inductances.
Well, Iíve been quite in a mood for talking, ha? :)