4.5V

4.5V used to be the voltage standard for the first electric components (e.g. motors, lights) in certain LEGO sets. The power came from a battery box with 3x 1.5V batteries.
Beside Basic sets and TECHNIC sets, the 4.5V standard was used for motorization of the first electric LEGO Trains which marked a long era from 1966 to 1986.
The 4.5V standard was later used for battery powered DUPLO Trains. 
== 4.5V powered Themes ==
* Basic
* Trains
* TECHNIC
* DUPLO > DUPLO Trains
== 4.5V powered Sets ==
===Basic===
* 088 4.5V Super Set (1969)
* 107 4.5V Reversible Power Unit (1971)
* 816 Lighting Bricks, 4.5V (1986)
* 970 Lighting Bricks (1978)
=== Trains ===
* 104 4.5V Replacement Motor (1970)
* 112 Locomotive with Motor (1966)
* 113 Motorized Train Set (1966)
* 118 Motorized Freight or Passenger Train (1969)
* 119 Super Train Set (1968)
* 120 Complete Freight Train with Tipper Trucks (1969)
* 127 Complete Train with 3 Wagons (1971)
* 133 Locomotive (1975)
* 161 Battery Wagon (1972)
* 162 Locomotive (1977)
* 180 4.5V Train with 5 Wagons (1972)
* 181 Train Set with Motor, Signals and Shunting Switch (1972)
* 182 Train Set with Motor (1975) - Train Set with Signal
* 183 Train Set with Motor and Signal (1976)
* 7710 Push-Along Passenger Steam Train (1980)
* 7720 Diesel Freight Train Set (1980)
* 7722 Steam Cargo Train Set (1985)
=== TECHNIC ===
* 870 Technical Motor, 4.5 V (1978)
* 8700 Power Pack (1982)
=== DUPLO ===
* 3771 Train Starter Set (2005)
* 3772 Deluxe Train Set (2005)
* 5608 Train Starter Set (2008)
* 5609 Deluxe Train Set (2008)
=== Service Packs ===
* 3 Battery Box (1977)
* 4 4.5V Motor Battery Cables (1977)
* 7 Train Signal with Ties (1981)
* 7 Battery Box (1981)
* 8 Replacement 4.5V Motor (1981)
* 11 Locomotive Traction Tires (1977) 
* 12 Wheel Bearings for Locomotives (1977)
* 15 Lighting Brick (2 x 2) (1977)
* 19 Locomotive Piston Assemblies (1977)
* 29 4.5V Motor (1977)
* 1101 Replacement 4.5V Motor (1980)
* 1103 Battery Box (1977)
* 1111 Rubber Rims for Locomotive Wheels (1977)
* 1112 Train Sliding Wheel Blocks (1977)
* 1115 Lighting Brick, 4.5V (1980)
* 1119 Locomotive Piston Assemblies (1977)
* 1138 Replacement Rubber Wheel Treads for Trains (1981)
* 1168 Battery Box (1986)
* 1175 4.5V Motor (1978)
* 5000 Replacement 4.5 V Motor (1987)
* 5001 4 Wheel Bushes for 4.5 V Basic Motor (1987)
* 5003 2 Lighting Bricks 4.5 V (1987)
* 5005 Battery Box Grey 4.5 V for use with Basic set 816 (1987)
* 5007 Basic Motor 4.5 V, Motor and Gear Housing. For use with set 810 (1989)
* 5075 Tender 4.5 V Battery Red. For Trains with Battery Motor 810 (1987)
* 5100 Battery Box (Tube) 4.5 V (1987)
* 5101 4.5V Motor for Technical Sets (1987)
=== Idea Books ===
* 241 4.5v Idea Book
==Complete List==
Category:Themes
Category:Basic
Category:Trains
Category:DUPLO Trains
Category:Service Packs
Category:4.5V
Category:TECHNIC