To convert to W (watts), enter the known values of A (amperes) and V (volts) in the corresponding boxes . Follow the same steps in the respective form if what you want is to find the value of A (amperes) or V (volts).
Volts, watts, and amperes are units used to measure different aspects of electricity. Here I explain the relationship and the differences between them:
The formula that relates them is P = V x I
Where P is the power in watts (W), V is the voltage in volts (V), and I is the current in amperes (A).
Volts (V)
- Definition : Volts measure electrical potential or the potential difference between two points in an electrical circuit. Essentially, it is the “pressure” that drives electrons to move through a conductor.
- Symbol: V
- Example: If you have a 12 volt battery , it means that there is a potential difference of 12 volts between the positive and negative terminals of the battery.
Amperes (A)
- Definition: Amperes measure electric current, which is the flow of electrons through a conductor. It indicates how many electrons are passing through a point in the circuit per second.
- Symbol: A
- Example: If a circuit has a current of 2 amperes, it means that 2 coulombs of charge are passing through a point in the circuit every second.
Watts (W)
- Definition: Watts measure electrical power, which is the rate at which energy is consumed or generated. It is the product of voltage and current.
Symbol: W - Example: If a device consumes 60 watts, and operates with a voltage of 120 volts, the current it consumes is 0.5 amperes (60 W / 120 V = 0.5 A).
Key differences
Measurement
Each one measures a different thing:
- Volts : electrical potential difference.
- Amperes : intensity of electric current.
- Watts : amount of electrical power.
Concept
- Volts refer to the force that pushes the electrons.
- Amperes refer to the number of electrons that are flowing.
- Watts refer to the energy used or generated per second.
Practical example
A 60 W portable photovoltaic panel connected to a 12 V outlet:
- Volts: 12 V (outlet voltage).
- Wattage: 60 W (solar panel power).
- Amps: I = P / V = 60 / 12 = 5 A (current flowing into the panel).
This relationship is fundamental in electricity and electronics to understand how devices work and how energy and electricity are consumed and transmitted.
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Origin and additional technical details
Volts (V)
- Origin of the term: The name “volt” comes from Alessandro Volta , an Italian physicist who pioneered electricity.
- Measurement: It is measured with a voltmeter. Voltmeters are connected in parallel with the device or section of the circuit whose potential difference is to be measured.
- Ohm’s Law: Relates voltage (V), current (I) and resistance (R) in a circuit. The formula is V = I x R , where R is the resistance in ohms (Ω).
- Types of voltage: It can be direct current (DC) or alternating current (AC). Batteries provide DC, while most household electricity supplies provide AC.
Amps (A)
- Origin of the term: The name “ampere” comes from André-Marie Ampère , a French mathematician and physicist who contributed significantly to the study of electrodynamics.
- Measurement: It is measured with an ammeter . Ammeters are connected in series with the device or section of the circuit whose current is to be measured.
- Direct current (DC) and alternating current (AC): Like voltage, current can be direct (constant flow in one direction) or alternating (flow that changes direction periodically).
- Current Capacity: Cables and components have a maximum current capacity that they can handle without overheating or being damaged.
Watts (W)
- Origin of the term: The name “watt” comes from James Watt , a Scottish engineer known for his improvements to the steam engine.
- Measurement: Power can be measured directly with a wattmeter or calculated using voltage and current readings.
- Active, reactive and apparent power: In alternating current systems, the power can be:
- Active (W): Power that does useful work, measured in watts.
- Reactive (VAR): Power that circulates between the generator and the equipment, measured in reactive volt-amperes.
- Apparent (VA): Combination of active and reactive power, measured in volt-amperes.
- Energy efficiency: The efficiency of electrical devices can be evaluated by considering how much energy they consume in watts and how much useful work they produce.
Practical applications
Homes and offices
Electronic devices and appliances are labeled with their power consumption in watts. This helps calculate electrical consumption and estimate energy costs.
Circuit engineering and design
In electronic circuit design, it is crucial to know voltages and currents to select appropriate components and ensure safe and efficient operation.
Renewable energy
In renewable energy systems such as solar panels or wind generators, it is important to measure and manage voltage, current and power to maximize efficiency and energy output.
Automotive
Electric vehicles use concepts of voltage, current and power to manage the storage of energy in batteries and the delivery of power to motors.
Complete illustrative example
Imagine an LED lighting system in a house:
- Voltage: The system is designed to operate on a 12V power supply.
- Current intensity: Each LED strip consumes 2 A of current.
- Power: The power consumed by the LED strip is P = V x I = 12 V x 2 A = 24 W
If you have four LED strips connected, the total power consumption would be 96W.
Knowing this allows you to properly size the power supply and predict energy consumption.
Quick conversion tables
Download our free quick conversion tables in pdf from amps to watts and from watts to amps, for different voltages.