How to measure IV- Curve of 1 Kilo Ohm using USB DAQ with DASYLab 2022?

[Syed Sibtul Hassan Sherazi]

Hi All,

Basically, I wanted to record/draw the IV Curve of the resistance (1 Kilo Ohm placed on the physical breadboard) via the Chart recorder or XY Graph of USB 202 DAQ with DASYLab 2022.

The input to one end of the resistor is the Analog Output (0 Volt to 1 Volt in 1 minute with 0.1 V step size) and the other end is grounded.

Now the question is how I can measure the current through resistance. And after measuring the current, how can I draw the IV Curve? I am confused as the Analog input of USB 202 DAQ takes voltage as input, not as current.

May I request to please assist me in this regard and tell me how I can do this?

Thanks.

[Syed Sibtul Hassan Sherazi]

Could anyone please reply to it? 

[Fausto]

Hello @Syed Sibtul Hassan Sherazi.

The analog output channel on an USB-202 can source a maximum output current of 5 mA per analog output channel, but it is a voltage supply source, not a current supply source.

https://files.digilent.com/manuals/USB-202.pdf

The analog input channels can be used to measure a 4-20 mA current loop as shown via the following link.

Measuring a 4-20 mA current loop video with an USB-201 and DAQami

Regards,

Fausto

[Syed Sibtul Hassan Sherazi]

Hi @Fausto,

This statement "The analog output channel on a USB-202 can source a maximum output current of 5 mA per analog output channel, but it is a voltage supply source, not a current supply source" means that analog output can give voltage directly but not the current. Am I right?  

As far as the second link is concerned, I have made the same circuit (See where 10 K resistor) which is placed between the channel (CH0) and ground (AGND) but in my case the voltage course to CH0 is from Analog Output (0 to 1 Volts) [See Breadboard where AOUT0 and CH0 are the same point and at the same potential).  

Please check my coding at the DASYLab 2022, but rather than having current as an output, I am getting the voltage which is exactly the same as the Analog Output Voltage. 

Now, could you please tell me how to resolve such an issue? My end goal is to draw the I-V curve of that resistor by using the Analog Output Voltage. Basically, the X-axis will be the analog voltage obtained from the output terminal and the y-axis will be the current flowing through the resistor.   

Thanks and looking forward to hearing from you soon.

[Syed Sibtul Hassan Sherazi]

Could you please reply me when free!

[Fausto]

Hello @Syed Sibtul Hassan Sherazi.

Your IV characteristics curve will be linear, because you are not using a current signal source instead of the analog output channel's voltage signal.

In any case, take a look at the attached DASYLab worksheet, which my colleague JRys created.

IV Curve.DSB

DEFWRITE.TXT

Regards,

Fausto