![](https://coimages.sciencemuseumgroup.org.uk/210/998/large_thumbnail_cd0439_009_081104_1996_10_807_ferranti_1b_stall_recovery_switching_unit.jpg)
![](https://coimages.sciencemuseumgroup.org.uk/210/998/large_thumbnail_cd0439_009_081104_1996_10_807_ferranti_1b_stall_recovery_switching_unit.jpg)
![](https://coimages.sciencemuseumgroup.org.uk/126/898/large_thumbnail_cd0701_028_121212_2003_22_120_3_mercury_switch.jpg)
Mercury switch
circa 1950
![](https://coimages.sciencemuseumgroup.org.uk/126/900/large_thumbnail_cd0701_030_121212_2003_22_120_4_mercury_switch.jpg)
Relay switch made by the Power Equipment Co. Ltd
circa 1950
![](https://coimages.sciencemuseumgroup.org.uk/126/897/large_thumbnail_cd0701_027_121212_2003_22_120_1_mercury_switch.jpg)
Mercury switch made by the Power Equipment Co. Ltd
circa 1950
![](https://coimages.sciencemuseumgroup.org.uk/210/985/large_thumbnail_cd0438_018_081104_1996_10_360_ferranti_1b_switching_unit.jpg)
Ferranti switching unit
![](https://coimages.sciencemuseumgroup.org.uk/210/933/large_thumbnail_cd0445_010_081106_1996_10_357_ferranti_1c_switching_unit.jpg)
Switching unit
![](https://coimages.sciencemuseumgroup.org.uk/126/903/large_thumbnail_cd0701_033_121212_2003_22_120_8_mercury_switch.jpg)
Mercury tube switch
![](https://coimages.sciencemuseumgroup.org.uk/126/901/large_thumbnail_cd0701_031_121212_2003_22_120_6_mercury_switch.jpg)
Mercury tube No. 9 for switch
![](https://coimages.sciencemuseumgroup.org.uk/126/902/large_thumbnail_cd0701_032_121212_2003_22_120_7_mercury_switch.jpg)
Mercury tube No. 9 for switch
![](https://coimages.sciencemuseumgroup.org.uk/128/709/large_thumbnail_cd0686_023_120423_2012_15_6_mazda_glass_starter_switch.jpg)
Mazda 80W glass starter switch
1950-1960