Symmetrical opamp supply - from a single battery source

A simple and well-known circuit: a symmetrical supply constructed with an opamp for opamps and of course other small circuits that require a positive as well as a negative supply voltage. Both voltages are derived from one battery. The resistors R1 and R2 form a high impedance, and therefore energy saving voltage divider. The opamp takes care that the artificial ground potential remains identical to the potential at the junction of R1 and R2. The relation- ship between R1 and R2 determines the relationship between the two output voltages; if R1 and R2 have the same value, the same will hold from a single battery source good for both output voltages (sym- metrical). This brings us to the most pleasant characteristic of the circuit, in that the relationship does not depend on the battery voltage! Another J. Wallaert 4.5V +4,5 V symmetrical opamp supply advantage of this active voltage divider is the fact that (in contrast to a simple resistor divider chain) it adapts itself well to chang