Abstract: A universal electronic payment terminal base comprising an application and transaction microprocessor (4), with its power supply source (8) and being capable of receiving information identifying memory card holders, and a reader (6) of these cards controlled by the microprocessor (4). The source (8) also serves for programming the cards and delivers a voltage at most equal to the smallest of the programming voltages required. Between the low weight source (8) and the reader (6) a voltage booster (51) is provided for boosting the voltage to a constant level higher than the largest of the programming voltages, and a step by step voltage dropper (53) controlled by a variable cyclic ratio pulse generator (36).