large digital clock

Many large digital clocks are AC (corded) or USB powered. Several models also include an optional small battery backup that preserves the time and date (and in some cases alarm settings) during power outages.

Brightness controls vary by model: bedside units often provide 3-level or a night-mode dimming option, while oversized wall clocks commonly offer multiple settings such as six brightness levels or high/low dimmer controls.

Large digital clocks are typically designed for wall mounting or desktop/shelf placement. Many oversized models include hardware so they can be hung on a wall or set on a shelf or desk.

Many models offer multi-function timing such as a built-in stopwatch and countdown timer, multiple alarm slots (some examples list up to eight alarms), and adjustable snooze timers. Exact features vary by model.

Some bedside and wall models include a room temperature readout, and a smaller number also show humidity. These features are typically listed in product specifications when included.

Common backup options listed for bedside alarm clocks include a 9V battery or 2×AAA batteries (often not included). Some models use a dedicated battery backup specifically to preserve time and alarm settings during power interruptions.