free impedance converter

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I'm no great programmer- couldn't even play one on TV. Regardless, here's a Windows version of a utility I've found handy for converting bridge results and vector impedance meter readings to a more useful form. It can also give more insights into the real meaning of Q, DF, and phase angle for common components. There's nothing here that any spreadsheet can't do, but I find a small dedicated utility a bit handier at times. Have a look and let me know if you see any horrific bugs, misspellings, or think of some feature I should add. There's room for lots more buttons :)

Z-verter Impedance Converter

Regards,
Conrad
 
Put up a new version with some bug fixes. Ditch the old one and grab the new one. (old version had atto and femto prefixes reversed) Added some more conversions, including current and voltage to value, so you can measure components with just a signal and AC voltmeter. If not doing it with a scope, just enter minus 90 degrees for capacitors, plus 90 for inductors. Same request- let me know if you find bugs or can think of anything useful to add. Or if it's just useless.
 
The symbols are pretty standard. The idea of the program is to convert any of the several ways of expressing impedance, into a standardized list containing all the forms.

The forms include component values like capacitance and dissipation, Z, the impedance consisting of resistance (R) and reactance (jX), Y, the admittance (reciprocal of impedance), consisting of conductance (G) and susceptance (jB), and vectors consisting of Z and phase angle. If you have any of the above types, you can calculate the other ones. They all give you the same information, but sometimes a certain form is more convenient.

Within the above forms you might use either a series or parallel loss model. Cs is capacitance using the series model for capacitance, where you have a series resistor accounting for the losses. Note that most capacitors have a somewhat constant dissipation factor with frequency, meaning that the series resistor is *not* constant with frequency. That's why you have to be careful using a fixed resistor in simulations. Cp is capacitance using the parallel model, where losses are accounted for with a resistor across the capacitor. That doesn't mean a real capacitor has that much DC leakage, but the model is only used for AC calculations. Ls and Lp are inductance, again using the series and parallel models. Note that G and B are invariably parallel quantities.

You'll also find a calculation for two Cs or Ls values. The old "add the values for parallel" technique doesn't take losses into account, so if you know the dissipation factor, you can get a more accurate result. Finally, there's a selection to enter voltage and current, as all the above can be calculated from that as well.

As a practical matter, I use the program to convert Z and Y results from one of my bridges, to practical component values. I also like to see what R is at a given frequency for capacitors and inductors. Note that I didn't include a button for Ls and R, as one would have a tendency to enter DC resistance of a coil. That's not very accurate much of the time, so one shouldn't be tempted. OTOH, if enough people want it...

I'm not sure where there's a good impedance tutorial, but there's probably something on the 'net. The intro for old GR bridges is usually good, and there might be some useful references on the Quadtech or IET websites.

I hope I got the above right...

Regards,
Conrad
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.