Most of op-amp circuits run from symmetrical bipolar supply source lets say Â±15V. The simplest way to generate symmetrical split supplies is to use a pair of 3 terminal voltage regulators. For instance lets take two voltage regulators: 7815 and 7915.
If you need an adjustable variant of dual polarity regulated voltage source you can use 317 and 337 adjustable regulators, where you can trim voltage with voltage divider which consists of two higher accuracy resistors:
You may wander if there are dual 3 terminal regulators in one casing â€“ yes they are. They are called â€œDual Tracking Regulatorsâ€. Dual tracking regulators are available as complete integrated circuits in both â€“ fixed and adjustable versions.
Typically there are 4195 for fixed Â±15V and 4194 is symmetrically adjustable via single resistor.