07-18-2014 06:40 AM
Hi everyone
I'm measuring charging and discharging two capacitors, individually.
I'm using the USB 6009;
Two capacitors, two graphs, two analog inputs (AI0 +, AI01 -) and (Al1 +, Ai1 -);
I configuredin differential mode; ok
Problem:
When a capacitor is switched off, it measures 1.4 V
Solved! Go to Solution.
07-18-2014 07:09 AM
Do you have a schematic of your circuit? What is happening when you turn the switch off?
07-18-2014 07:37 AM
Hi, Sorry my english is not very good..
What is happening when you turn the switch off?
R: USB 6009 Analog Input Reads Approximately 1.4 ,
Thank you
07-18-2014 07:56 AM
Let me rephrase that. What does your circuit do when you turn the switch off? Is the capacitor left there with nothing connected? Do you connect something to drain the charge on the capacitor?
SHOW US YOUR CIRCUIT'S SCHEMATIC.
07-18-2014 08:46 AM
Thanks for your help!! croossrulz
What does your circuit do when you turn the switch off?
R: The capacitor discharges, 0V.
Is the capacitor left there with nothing connected? Do you connect something to drain the charge on the capacitor?
R: Resistor 1M
07-18-2014 08:52 AM
Circuit new
07-18-2014 09:04 AM
Sorry!!
What does your circuit do when you turn the switch off?
R: The capacitor discharges, and Usb 6009 Analog Input Reads Approximately 1.4V ..... I want to 0V..
Thank you
07-18-2014 09:17 AM
Try setting up the task correctly- Use the DAQ Wizard to create the Task
Dev1/ao0 would be much better- Oh, and now that you have the Wizard open- Do look at the wiring diagram it provides you with
For 6009 DIFFERENTIAL mode task AI0 is + AI3 is - and you only reserve explicitly reserve AI0 (The AI3 line is reserved by seleting the + line in the channel and declairing that it is differential)
And give the Task/Channel a meaningful name "MyCap1Discharge" would be helpful.......
Now let's speak about your electrical engineering:
The input impedance of the 6009 is 144kOhms The 1MOhm discharge resistor becomes moot as soon as you connect the monitoring 6009 AI.
07-18-2014 11:25 AM
Thank you Jeff Bohrer
Thank you Crossrulz
Sorry my english is not good
well, the circuit worked, I removed the1M resistor and put 10k
Saile