Analog Discovery Networkanalyzer dB-->V

[Amani]

Hi,

I recently bought Analog Discovery.

Very handy toolset!

I would like to measure LC impedance with network analyzer.

There is an example "Measuring loudspeaker impedance". On my wavelab version (2.7.5) I can't find the option to change magnitude representation to show voltage instead dB.

Can I set it somewhere else?

Would it be possible to "automate" the measurement with some kind of script to directly display impeance @ cursor point (defining shunt resistor for current measurement in setup)?

 

Thanks!

 

Kind regards

[attila]

Hello,

 

In WaveForms2 Network Analyzer magnitude is available only in dB representation. The export lets you choose gain units.

 

There is a test instrument, not fully working, of Impedance Analyzer. Having WaveForms main window in front type "nolimits", the window title will change and under More instruments you will have Impedance Analyzer.

Follow the connection schematic shown in the instrument: AWG 1 connected to Scope channel 1; Scope channel 2 connected to ground with a reference resistor and its value specified in the interface; insert the L/C component to measure between the scope channels. This test setup can be made on a breadboard.

In the dropdown after the L/R/C symbol you can choose between series/parallel approximation, L/C.

 

[Amani]

Hi Atilla,

 

Wow, thats "neat", magic password ;-)

That Impedance analyzer looks really nice:

For my purpose I would need LC parallel circuit analyzing, L(inductor) in parallel to capacitor. Impedance of LC changes with inductor load, with analyzer I could see what's actual impedance on a LC circuit with changing inductor loading.

In WaveForms2 Network analyzer: if I export in gain units: How can I calculate volts?

 

Thanks a lot for your support!

 

kind regards 

[attila]

The magnitude (gain or dB) is relative to the specified AWG amplitude. Volt = Amplitude x Gain; Gain = 10^dB/20

[Amani]

Hi,

I'm a bit confused:

Channel 1 voltage is calculated from AWG amplitude x channel 1 gain. Channel 2 voltage is channel 1 voltage x channel 2 gain?

Wouldn't it be easier to export it directly in volts?

[attila]

You have the in WaveForms3 in private message.

Using this version, under Channel 1 uncheck "Use as Reference" and under Magnitude options (gear) select Vpeak units.

For resonant circuits you might need to increase the settle time, under Bode/Wavegen options. This, to leave the circuit discharge the accumulated energy of previous frequency step.