BLOG

What is A21 Bulb

Horace He

Last Updated: December 26, 2023

What is A21 Bulb

An A21 bulb is a type of light bulb commonly used in domestic lighting applications. It is named A21 because it has a diameter of 21-eighths of an inch or approximately 2.625 inches. This bulb is characterized by its pear-shaped design, similar to the A19 bulb. The A21 bulb is typically used in various household fixtures such as table lamps, ceiling fans, and wall lights.

Maybe You Are Interested In

  • Load Current: 10A Max
  • Auto/Sleep Mode
  • Time delay: 90s, 5min, 10min, 30min, 60min
  • Load Current: 10A Max
  • Auto/Sleep Mode
  • Time delay: 90s, 5min, 10min, 30min, 60min
  • Load Current: 10A Max
  • Auto/Sleep Mode
  • Time delay: 90s, 5min, 10min, 30min, 60min
  • Load Current: 10A Max
  • Auto/Sleep Mode
  • Time delay: 90s, 5min, 10min, 30min, 60min
  • Load Current: 10A Max
  • Auto/Sleep Mode
  • Time delay: 90s, 5min, 10min, 30min, 60min
  • Load Current: 10A Max
  • Auto/Sleep Mode
  • Time delay: 90s, 5min, 10min, 30min, 60min
  • Occupancy mode
  • 100V ~ 265V, 5A
  • Neutral Wire Required
  • 1600 sq ft
  • Voltage: DC 12v/24v
  • Mode: Auto/ON/OFF
  • Time Delay: 15s~900s
  • Dimming: 20%~100%
  • Occupancy, Vacancy, ON/OFF mode
  • 100~265V, 5A
  • Neutral Wire Required
  • Fits the UK Square backbox
  • Voltage: DC 12V
  • Length: 2.5M/6M
  • Color Temperature: Warm/Cold White
  • Voltage: DC 12V
  • Length: 2.5M/6M
  • Color Temperature: Warm/Cool White
  • Voltage: DC 12V
  • Length: 2.5M/6M
  • Color Temperature: Warm/Cool White
  • Voltage: DC 12V
  • Length: 2.5M/6M
  • Color Temperature: Warm/Cold White
rz036 occupancy sensor switch ceiling mounted
  • Occupancy mode
  • 12V ~ 24V, 5A
  • Neutral Wire Required
  • 1600 sq ft
  • Voltage: DC 12v/24v
  • Day/Night Mode
  • Time delay: 15min, 30min, 1h(default), 2h
  • Occupancy, Vacancy, ON/OFF mode
  • 100~265V 5A
  • Neutral Wire Required
  • Fits the US 1-Gang wall box
  • Occupancy, Vacancy, ON/OFF mode
  • 100~265V, 5A
  • Neutral Wire Required
  • Fits the US 1-Gang wall box
  • Occupancy, Vacancy, ON/OFF mode
  • 100~265V, 5A
  • Neutral Wire Required
  • Fits the European round backbox
rz021 us occupancy vacancy sensor switch front
  • Occupancy, Vacancy, ON/OFF mode
  • 100~265V, 5A
  • Requires Hot wire, Load wire
  • No Neutral/Ground Wire Required
  • Fits the US 1-Gang wall box
rz023 uk occupancy vacancy sensor switch front
  • Occupancy, Vacancy, ON/OFF mode
  • 100~265V, 5A
  • No Neutral/Ground Wire Required
  • Fits the UK square pattress box

One notable feature of the A21 bulb is its ability to produce strong and bright illumination. It is designed to accommodate higher wattages, resulting in a higher light output compared to smaller bulbs like the A19. This makes the A21 bulb suitable for rooms or areas that require ample lighting.

In terms of compatibility, the A21 bulb has a standard medium bulb base, allowing it to fit into most light fixtures. It offers a 360-degree beam angle, providing omnidirectional illumination. However, it is important to note that while the A21 bulb produces strong light, it does not fill the same amount of space with light as an A19 bulb.

Additionally, the larger size of the A21 bulb helps to dissipate heat more effectively, making it a suitable choice for LED lights. This is particularly important as excessive heat can damage the internal electronics of LED bulbs. However, it is worth considering that A21 bulbs tend to use more energy compared to smaller bulbs like the A19, so energy efficiency may be a consideration when choosing between the two.

Looking For Motion-Activated Energy-Saving Solutions?

Contact us for complete PIR motion sensors, motion-activated energy-saving products, motion sensor switches, and Occupancy/Vacancy commercial solutions.

Leave a Comment

en_USEnglish