A system to deposit drops on a substrate includes a dispenser to dispense the drops, a shutter disposed between the dispenser and the substrate to focus the drops, and a screen, disposed between the dispenser and the shutter, configured to provide a charge to the drops. User credentials are stored in a personal security module and in an authentication server. Wherein the switching capacitor network, receives an analog signal and a plurality of clock signals from the clock generator, where the switching capacitor network stores a portion of charges of the analog signal according to one clock signal, and outputting the portion of charges in according to another clock signal.