Designing an instrument for the measurement of very low electric current has a few challenges. Here, at KAFTS, we have decided to undertake the task of investigating is it possible to design a cost-sensitive, digital DC picoammeter. We have set an additional objective that the sensing resistor resistance shall be as low as possible. This goal is challenging due to thermal noise, which raises proportionally to the square root of resistance. With the higher resistor value, the useful signal to noise ratio is better for a given electric current value. Nevertheless, thanks to smaller resistance, the drop voltage is also less significant, making the device more beneficial with specific transducers.
The result was very positive. We came out with the battery-powered, digital and low-cost device that provides an easy user interface and auto-calibration functionality.
Our device already found applications in molecular biology and spectrometry, fascinating disciplines!
We also want to thank the Physics Open Lab for the fantastic review. We are happy that our picoammeter is a part of such a great laboratory!
If you wish to buy our product, please note that it is available on eBay.
Minimum Resolution: 1 pA.
Maximum Current: +- 50 mA.
Error: +- (2% + 2).
Three Modes of Operation:
Mode 1 - Resolution: 1 pA, Range: +- 500 nA, Sensing Resistor: 1 MOhm.
Mode 2 - Resolution: 1 nA, Range: +- 500 uA, Sensing Resistor: 1 kOhm.
Mode 3 - Resolution: 1 uA, Range: +- 50 mA, Sensing Resistor: 10 Ohm.
Screen / measurement refresh frequency: 2 Hz.
Maximum current stabilization time from max positive to max negative: 10 seconds.
Operating temperature range: 10 - 30 Degrees Centigrade.
Operating humidity range: 20% to 60%.
Dimensions: 100 mm x 100 mm x 26 mm.