What type of dimmer can be turned on and off by a separate switch?

A three-way dimmer is designed specifically to be used in setups where you want to control a single light or a group of lights from two different locations. It allows one switch to turn the light on and off while the other switch (the three-way dimmer) can adjust the brightness. This makes it highly functional in areas like hallways or large rooms with multiple access points.

The configuration of a three-way dimmer supports the use of a separate switch, meaning that you can have a standard light switch in one location that controls the power to the circuit while the dimmer in another location adjusts the light's intensity. This functionality is key in creating adaptable lighting solutions based on user preference for brightness and convenience.

Other types of dimmers mentioned do not provide the same functionality in relation to being controlled by a separate switch. For instance, multi-scene controls are more sophisticated and cater to preset lighting scenes rather than basic on/off functionality. Photocells are typically used for automatic light control based on daylight levels rather than manual control, and smart dimmers, while offering advanced features through smart home systems, are generally controlled through apps or voice commands and may not align with traditional switch setups.