9V

9V (later marketed as the Electric System or the 9V-powersystem, depending on country) was a voltage standard for electrical components (e.g. motors, lights) in many LEGO sets. It first appeared in 1985 in the Light & Sound series of Town and Space models that featured flashing lights and sirens, and was later expanded to the Monorail sets.
TECHNIC also moved over to the 9V system in 1990, with Trains making the change the following year.
The power came from a battery box with one 9V PP3 type battery (e.g. or later with 6x 1.5V batteries (TECHNIC, Basic). The 9V system sought to address the major weakness with the preceding 4.5V and 12V systems which was the pinned plug connectors that were prone to coming loose or the wires that would eventually fracture and fail after heavy use. The new system used special bricks that contained conductive elements built into the studs which were connected more positively and were more reliable over long periods of use. Wired connections were still used whenever power had to be transmitted through awkward routes, but the terminations used the conductive brick connectors in place of the pinned plugs.
The Trains theme was the only application of 9V that was powered by a mains DC Transformer and special metal conducting rails for 9V Trains (without any add-on center conductor rails that were used by the earlier 12V Trains system). Controversially however the 9V Trains system lost most of the accessories of the 12V system such as remote-controlled signals, points and lights.
Mindstorms used the 9V system until the release of Mindstorms NXT in 2006, which was backwards compatible with the 9V standard with use of 8528 Converter Cables for Mindstorms NXT.
The 9V standard was retired in 2009 and replaced with the Power Functions system, which used the same voltage and was backwards compatible with the 9V standard with use of 8871 Power Functions Extension Wire 20” and 8886 Power Functions Extension Wire.
== 9V Components ==
===Wires & Adaptors===
===Power Sources===
===Motors===
===Lights & Sounds===
===Sensors===
===Train Tracks===
===Combination Sets===
==9V Powered Sets==
===Basic===
===Town===
===Space===
===Trains===
===TECHNIC===
===Mindstorms, Educational, and Dacta===
===Studios===
===Znap===
===Inventor & Creator===
Category:Themes
Category:Basic
Category:Town
Category:City
Category:World City
Category:Trains
Category:Space
Category:TECHNIC
Category:Service Packs
Category:9V
Category:Light & Sound
Category:Monorail