An electroscope will deflect its vane but this instrument shows the charge digitally in Coulombs up to 199 nano Coulombs, Accuracy + 10 nano Coulombs.

The display will show the number of Coulombs deposited into the instrument.

Coulomb Meter is a useful tool and behaves similarly to a Digital Electroscope.  

Either by current through a resistance or from a capacitor or from a source of static electricity (a charged plastic rod).