Measuring waveform of small current pulse

You can always run multiple loops through the current probe to gain the signal.

snipped-for-privacy@hotmail.com wrote:

I don't know your tools parameters but this is quite easy with an appropiate curent to voltage converter. 1uA...10uA and 1uS rise time is not a special wave form. A common voltage to current converter using a fast OA will do it.

greetings, Vasile

was "Measuring waveform of small current pulse"

Dave answered...

Just to answer wrt a AM503A, with a standard probe its most sensitive setting is 1mA/div. The scope input is set to its 10mV/div setting, and with a 50-ohm termination. With these settings, and with the 5MHz BW limit, my measured noise was just a bit larger than the scope trace. With the scope gain changed to 1mV/div = 100uA/div, the noise was about 1div, or 100uA p-p. Filtering the signal at 10kHz dropped the noise to 0.4mV or about 40uA p-p and the scope reported 13uA rms noise.

There was also a fairly large amount of dc drift, which means such measurements are most easily made with ac coupling.

As Dave says, you can run multiple loops through the probe to obtain a proportional improvement, perhaps up to 10x max. If your pulse is repetitive, you can further improve the SNR by putting your scope into averaging mode. Using all these tricks, a 1uA pulse measurement might barely be possible.

BTW, a second probe I tried was noisier. YMWV.

The resolution is probe dependant, the ACP312 is the most sensitive, they are all more than fast enough.

Try: