A system for identifying a molecule, comprising: a voltage control unit controlling a voltage source; a pair of electrodes (110, 116; 610, 616) coupled to the voltage source; and a measurement circuitry (112; 612); characterized in that the voltage control unit is configured to: draw a molecule to a nanopore by controlling the voltage source to apply a first voltage signal to the pair of electrodes (110, 116; 610, 616) during a first period, wherein the first voltage signal causes a first ionic current through the nanopore that is indicative of a property of a portion of the molecule proximate to the nanopore; release the molecule from the nanopore by controlling the voltage source to apply a second voltage signal to the pair of electrodes (110, 116; 610, 616) during a second period, wherein the second voltage signal causes a second ionic current through the nanopore; and determine the first period and the second period based at least in part on a net ionic current through the nanopore comprising the first ionic current and the second ionic current, wherein determining the first period and the second period based at least in part on the net ionic current comprises determining the first period and the second period that reduce the net ionic current, wherein determining the first period and the second period that reduce the net ionic current comprises setting the second voltage signal to a signal with a polarity opposite from the first voltage signal; the first voltage signal during the first period and the second voltage signal during the second period comprise an AC signal; the voltage control unit is further configured to set a duty cycle of the AC signal based at least in part on a sum of charges corresponding to the first ionic current and the charges corresponding to the second ionic current over a combined time period comprising the first period and the second period; and the measurement circuitry (112; 612) is configured to measure the first ionic current. a voltage control unit controlling a voltage source; a pair of electrodes (110, 116; 610, 616) coupled to the voltage source; and a measurement circuitry (112; 612); characterized in that the voltage control unit is configured to: draw a molecule to a nanopore by controlling the voltage source to apply a first voltage signal to the pair of electrodes (110, 116; 610, 616) during a first period, wherein the first voltage signal causes a first ionic current through the nanopore that is indicative of a property of a portion of the molecule proximate to the nanopore; release the molecule from the nanopore by controlling the voltage source to apply a second voltage signal to the pair of electrodes (110, 116; 610, 616) during a second period, wherein the second voltage signal causes a second ionic current through the nanopore; and determine the first period and the second period based at least in part on a net ionic current through the nanopore comprising the first ionic current and the second ionic current, wherein determining the first period and the second period based at least in part on the net ionic current comprises determining the first period and the second period that reduce the net ionic current, wherein determining the first period and the second period that reduce the net ionic current comprises setting the second voltage signal to a signal with a polarity opposite from the first voltage signal; the first voltage signal during the first period and the second voltage signal during the second period comprise an AC signal; the voltage control unit is further configured to set a duty cycle of the AC signal based at least in part on a sum of charges corresponding to the first ionic current and the charges corresponding to the second ionic current over a combined time period comprising the first period and the second period; and the measurement circuitry (112; 612) is configured to measure the first ionic current. draw a molecule to a nanopore by controlling the voltage source to apply a first voltage signal to the pair of electrodes (110, 116; 610, 616) during a first period, wherein the first voltage signal causes a first ionic current through the nanopore that is indicative of a property of a portion of the molecule proximate to the nanopore; release the molecule from the nanopore by controlling the voltage source to apply a second voltage signal to the pair of electrodes (110, 116; 610, 616) during a second period, wherein the second voltage signal causes a second ionic current through the nanopore; and determine the first period and the second period based at least in part on a net ionic current through the nanopore comprising the first ionic current and the second ionic current, wherein determining the first period and the second period based at least in part on the net ionic current comprises determining the first period and the second period that reduce the net ionic current, wherein determining the first period and the second period that reduce the net ionic current comprises setting the second voltage signal to a signal with a polarity opposite from the first voltage signal; the first voltage signal during the first period and the second voltage signal during the second period comprise an AC signal; the voltage control unit is further configured to set a duty cycle of the AC signal based at least in part on a sum of charges corresponding to the first ionic current and the charges corresponding to the second ionic current over a combined time period comprising the first period and the second period; and the measurement circuitry (112; 612) is configured to measure the first ionic current.