Power Converter

James Watt needed a way to market his steam engines. He observed that a typical draft horse could lift 550 pounds by 1 foot in 1 second. This rate of work (550 ft·lbf/s) became the definition of one horsepower. This helped potential buyers understand the capability of his engines in familiar terms.

In electrical circuits, power (in watts) can be calculated as P = V × I, where V is voltage (in volts) and I is current (in amperes).

A healthy human can sustain an average power output of about 100-200 watts during moderate exercise. Professional cyclists can generate over 400 watts for extended periods.

The Sun radiates an immense amount of power, approximately 3.8 x 10²⁶ watts. Only a tiny fraction of this power reaches the Earth.

Brake horsepower is the power measured at the flywheel of an engine before any losses from the drivetrain (gearbox, alternator, etc.). It represents the engine's 'true' power output.

The acoustic power of a sound source is measured in watts. A normal conversation might produce only a few microwatts of sound power, while a large rock concert sound system can output many thousands of watts.

Efficiency is the ratio of useful power output to total power input. For example, an incandescent light bulb is only about 5% efficient at converting electrical power to visible light power; the rest is lost as heat. LEDs are much more efficient, at over 25%.

In radio and telecommunications, power levels are often expressed in dBm, a logarithmic scale where 0 dBm is defined as 1 milliwatt (mW). This scale is convenient for representing both very large and very small power levels.

In HVAC, a 'ton of refrigeration' is a unit of power. It's the rate of heat transfer required to freeze one short ton (2000 lbs) of water into ice at 0°C in 24 hours. It's equivalent to 12,000 BTU/hour or about 3.5 kW.

The wattage of a solar panel is its rated power output under standard test conditions (full sun, specific temperature). The actual power it generates varies with sunlight intensity, angle, and temperature.

This ratio (e.g., hp/kg or W/kg) is a critical performance metric for vehicles, especially aircraft and race cars. A higher ratio indicates better acceleration.

Geothermal power plants harness the immense heat from the Earth's core. They use steam from underground reservoirs to turn turbines and generate electricity, often producing hundreds of megawatts.

The power generated by a wind turbine is proportional to the cube of the wind speed. This means that doubling the wind speed increases the available power by a factor of eight.

The erg per second is the CGS unit of power, corresponding to the CGS energy unit (erg). One watt is equal to 10 million ergs per second. It is a very small unit and rarely used today.

'Vampire power' or 'standby power' refers to the electricity consumed by electronic devices when they are switched off or in standby mode. This can account for a significant portion of household energy use.

Car manufacturers usually advertise engine (or brake) horsepower. The actual power delivered to the wheels is always lower due to frictional losses in the drivetrain (transmission, driveshaft, etc.). A chassis dynamometer measures horsepower at the wheels.

A large lightning bolt can have a peak power of over a trillion watts (a terawatt), but it only lasts for a few microseconds. A hurricane can sustain a power level equivalent to many thousands of nuclear power plants.

'PS' stands for Pferdestärke, which is German for horsepower. It's the common term for metric horsepower and is widely used in Europe and Asia. 1 PS is defined as the power needed to lift 75 kilograms by one meter in one second.