A completely digital generator for producing timing and sampling pulses adjustable in 1 mS increments for rapid-scan differential pulse voltammetry (DPV) when interfaced to a commercially available electrochemical analyzer is reported. The generator is a self-contained unit and costs about $100 to build. The design given is specifically intended to interface with the Princeton Applied Research Model 174 Electrochemical Analyzer (PARC 174), although it can be easily modified to work with any suitable commercial or non-commercial instrument. Using ordinary recorder read out and the PARC-174 signal processing electronics, direct and inverse DPV can be done at scan rates up to 200 mV/s with the same reproducibility and accuracy obtained with the scan rates usually used in DPV (2-10 mV/s). With faster read out devices, practical analytical measurements can easily be done at scan rates of 0.5 to 1 V/s.