Final answer:
Older computer PSUs required a -5V voltage rail for components like RAM, motherboard logic, and ISA cards. Conductors like copper facilitate the flow of electricity, while insulators such as rubber and plastic protect against electrical hazards.
Step-by-step explanation:
The -5V voltage rail in older types of computer PSUs (Power Supply Units) was once required for legacy components like certain types of RAM, motherboard logic, and ISA cards. These components needed the -5V rail to operate properly. However, in modern systems, the -5V rail is no longer necessary and has been removed from the ATX12V standard since the components that required it are obsolete.
Conductors and insulators are essential in the design of power supplies and cables. Conductors like copper, which is most commonly used in electronics, allow electrons to move freely and thus enable the transfer of electric power. Insulators, such as rubber and plastic, are used to shield these conductors, preventing electric charges from escaping outward and providing safety from electrical hazards.
When discussing the components of a PSU, one might refer to a computer jack or a plug, which are used to connect the power supply to other components, ensuring the transfer of electricity. The -5V rail would be part of the internal circuitry and wiring of the PSU, which conducts power to the necessary components of the computer system.