What is milliwatt?
A milliwatt is a unit of power equal to one thousandth of a watt. It is used in low-power electronics, wireless communication systems, laser specifications, and medical device power ratings.
Real-world uses
Milliwatts measure the power of laser pointers (Class 1: <1 mW; Class 3B: up to 500 mW), Bluetooth radios (typically 1–100 mW), Wi-Fi transmitters, and fibre optic signals. They are used in optical communications, consumer electronics, and medical laser specifications.
History
Milliwatts became relevant as the miniaturisation era brought small electrical and optical devices into widespread use from the mid-20th century. Consumer electronics, telecommunications, and biomedical equipment all required power specifications at this sub-watt scale.
Common mistakes
Confusing milliwatts (mW) with microwatts (µW)—1 mW = 1,000 µW. Also, assuming all laser pointers operate at the same power level; safety regulations classify lasers by output power in mW, and even small increases can be hazardous to the eyes.
What is ton of refrigeration?
A ton of refrigeration is a power unit measuring the heat removal capacity of cooling systems, equal to 12,000 BTU per hour. It is the standard capacity rating for commercial and industrial air conditioning units in the United States.
Real-world uses
The ton of refrigeration (TR) is used for rating commercial and industrial cooling systems, chillers, and large-scale HVAC equipment. A small commercial building might need a 20–100 TR chiller. Data centres measure cooling capacity in TR. One TR = 12,000 BTU/h = approximately 3.517 kW.
History
The ton of refrigeration originated in the 19th century ice trade, when mechanical refrigeration systems were judged by their ability to replace ice delivery. One ton was defined as the cooling equivalent of melting one ton of ice per day. As mechanical refrigeration displaced natural ice by the early 20th century, TR became a standard industrial cooling unit.
Common mistakes
Confusing refrigeration tons with metric tons of mass—they are completely unrelated. Also, the "ton" in TR originated from the cooling power needed to melt one short ton (2,000 lb) of ice in 24 hours, not from any mass being cooled.
When is this conversion used?
Converting between milliwatt and ton of refrigeration is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region.
Worked examples
1 milliwatt = 2.843451e-07 ton of refrigeration
1 ton of refrigeration = 3,516.85284 watt
How to convert milliwatt to ton of refrigeration
To convert milliwatt to ton of refrigeration, multiply the value by 2.843451e-07.
To convert ton of refrigeration back to milliwatt, multiply by 3,516,852.84.
Measurement standards
The watt is the SI derived unit of power, defined as one joule per second (kg·m²/s³). Horsepower remains in widespread informal use, particularly in the automotive industry, but has no single universal definition across regions.
Did you know?
The human body at rest produces about 80 watts of power — roughly enough to keep an incandescent light bulb glowing. During intense exercise, a trained cyclist can sustain over 400 watts, and elite sprinters briefly exceed 2,000 watts.
Quick reference: milliwatt to ton of refrigeration
| milliwatt | ton of refrigeration |
|---|---|
| 0.1 | 2.843451e-08 |
| 0.5 | 1.421726e-07 |
| 1 | 2.843451e-07 |
| 2 | 5.686903e-07 |
| 5 | 0.00000142 |
| 10 | 0.00000284 |
| 25 | 0.00000711 |
| 50 | 0.00001422 |
| 100 | 0.00002843 |
| 250 | 0.00007109 |
| 500 | 0.00014217 |
| 1,000 | 0.00028435 |
Common values
| milliwatt | ton of refrigeration | |
|---|---|---|
| LED light bulb | 10,000 milliwatt | 0.00284345 ton of refrigeration |
| Desktop computer | 300,000 milliwatt | 0.08530354 ton of refrigeration |
| Microwave oven | 1,000,000 milliwatt | 0.28434514 ton of refrigeration |
| Small car engine | 75,000,000 milliwatt | 21.32588522 ton of refrigeration |
| Wind turbine (large) | 3.000000e+09 milliwatt | 853.03540878 ton of refrigeration |
Available Power units
More milliwatt conversions
- Convert milliwatt to watt
- Convert milliwatt to kilowatt
- Convert milliwatt to horsepower (mechanical)
- Convert milliwatt to megawatt
- Convert milliwatt to gigawatt
- Convert milliwatt to microwatt
- Convert milliwatt to BTU per hour
- Convert milliwatt to kilocalorie per hour
- Convert milliwatt to ton of refrigeration
Assumption: horsepower values use mechanical horsepower.