Whichever is deemed to be true, linear voltage regulators haven’t changed much in terms of design ... negative current on the same circuit. 7805 IC voltage regulator schematic.

Voltage regulator IC’s, with 3 pins, from LM7805 and LM7812 series are excellent for usage in voltage regulator circuits. If you need higher currents, up to 3 A, you must add a complementary ...