Simple Gratis Symmetrical Opamp Supply Voltages

Many ways to obtain a set of symmetrical supply voltages for operational amplifiers and comparators from a single +5-V sup-ply voltage have been described already. The simplest option (including with regard to component availability and price) is to use a MAX232, which is available in the 16-pin DIP package for less than 30 p (50 eurocents).In nearly all microcontroller circuits with an