I wonder if there is any way or personal experience to manually set a compliance current value, in case when doing I-V measurement using ordinary generator and two ordinary multi-meters?
Well,, please define your problem more detail. For instance what do you mean “ordinary generator" do you mean square wave function generator or sawtooth wave (or saw wave) generator or sine wave which one and if your answer one of these option. Could you please explain me what is your amplitude level and frequency order? Please keep in mind that it is very difficult to measure pA/nA scale current level with this equipment (almost impossible!).
Regards
To simulate a DC voltage sweep , I set the generator to saw wave (zigzag) mode and choose very low frequency, about 0,0007 Hz, so the the one saw is being drawn for about 20 mins. Amplitude level can different, depends on the materials we measure, but usually from 3V to 10V.
And what I need is - to set some compliance current value (let's say 10mA), to avoid breakdown of the sample.
If you expect 10 mA current at 10 V, then the resistance of your sample will be around 1kilo ohms which you can measure by multimeter even without worrying electromagnetic shielding. The breakdown in the sample can be due to joule heating at higher currents or due to some switching phenomena at certain voltages in case of a device. Current level of mA is quite safe in ordinary material if no switching phenomenon is expected. The exact value of maximum current level will be dependent on the material used.
What I need in practice is to set some value, like 10 mA, and so the increasing of current along with voltage would stop at this current, even if the voltage is continuing to increase. Like, if I sweep to 10 V, but the current on 6 V reached 10 mA, it would stay 10 mA up until the voltage is going towards 10V.
However, I guess, having only common devices it's impossible to accomplish?
As far as I know, compliance current value brings a current limitation during the I-V measurements, this is the good way to avoid sample breakdown. If your purpose is something like that then you have to know electrical power output capacity of your signal generator. For instance; if your signal generator power = 10 watt then at 1 V level you are going to be able to drive 10 Amp current level to your sample. And this amplitude is enough level to breakdown your sample. Therefore, I really would like to recommend you to use medium power operational amplifier as a buffer to limit your current level. In my experience if I do not remember it wrong LF351 op.amp has a maximum output current level approximately 30 mA. If you use LF 351 op.amp as a buffer amplifier, your problem will be solved. However, band frequency of LF351 is limited to 1MHz.
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