100M based nano-ampere current detection circuit

Kaixin micro test ESD18VB03-0201

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

5032 100M

微盟ME2188A33PG

This circuit can be used as a sensitive current detector or as a high input impedance voltage detector. Adjust R1 so that the voltage at point A is 1/2-3.1V lower than the ignition voltage of 2N494C. Only 40nA of input current is required to charge C2 and the gate level is raised to the ignition level. Once 2N494C is turned on, capacitors C1 and C2 are discharged through a 27Ω resistor, resulting in a positive pulse with sufficient amplitude. Trigger a semiconductor controlled rectifier or other pulse sensitive circuit.