10mA is enough to lose control of your muscles. 4mA is incredibly insensitive [1] compared to a more direct measurement, with volts from electrons, rather than

10mA is enough to lose control of your muscles. 4mA is incredibly insensitive [1] compared to a more direct measurement, with volts from electrons, rather than trying to measure their weak magnetic field, at a distance, as they zip by. With a sense resistor, you can use a bench top voltmeter [2] to measure nA. 1. 10fA resolution, over 400 billion times more sensitive: https://smt.at/en/products/electrometer-nv-meter/picoamperemeter-von-keithley-instruments-2/ https://smt.at/en/products/electrometer-nv-meter/picoamperem... 2. > 1 million times more sensitive, with GΩ sense resistor: https://www.keysight.com/us/en/assets/7018-06774/data-sheets/5968-0162.pdf https://www.keysight.com/us/en/assets/7018-06774/data-sheets...