The original DC generator was replaced by an alternator controlled by a voltage regulator. All other voltages are generated by voltage regulator modules on the motherboard. A more efficient alternative to a shunt voltage regulator is an active voltage regulator circuit. A voltage regulator tube was used in the Mark 6 exploder. The voltage regulator compensates for the change in load. Ripple may be reduced by an electronic filter, and eliminated by a voltage regulator. No external resistors, crystal, voltage regulator, EEPROM or other components are required. Many laptop and desktop motherboards include interleaved buck regulators, sometimes as a voltage regulator module. The LM317 is a popular adjustable positive linear voltage regulator. Some voltage regulator tubes have an internal jumper connected between two of the pins. Krypton-85 was used in cold-cathode voltage regulator electron tubes, such as the type 5651. A generic DVS system has a performance manager, a phase-locked loop and a voltage regulator. This regulator is often used as a "pre-regulator" in more advanced series voltage regulator circuits. In our hypothetical SoC the analog module only includes a voltage regulator. This device, the LM109 voltage regulator, was released in 1969 and at first went unnoticed.