Energy

/ˈpaʊər/

noun … “Rate of doing work or transferring energy.”

Power in electrical systems is the rate at which energy is transferred or converted by an electrical circuit. It is determined by the product of voltage and current, representing how much work is being done per unit time. Power is a critical measure for sizing circuits, selecting components, and understanding energy consumption.

Key characteristics of Power include:

• Unit: measured in watts (W), where 1 W = 1 V × 1 A.
• DC power: P = V × I, with voltage and current constant over time.
• AC power: can include real, reactive, and apparent power, depending on phase difference between voltage and current.
• Energy relation: total energy consumed over time is the integral of power (E = ∫ P dt).
• Heat and work: power determines how quickly energy is delivered to loads, producing motion, light, or heat.

Applications of Power include electrical appliances, motors, lighting, batteries, and energy management systems.

Workflow example: Calculating power in a DC circuit:

voltage = 12       -- volts
current = 2        -- amperes
power = voltage * current
print(power)       -- 24 W

Here, the circuit delivers 24 watts of power, converting electrical energy into useful work or heat.

Conceptually, Power is like the strength of a river: it measures how much water (energy) flows through per second to do work on a waterwheel.

See Voltage, Current, Resistance, Energy, Electricity.

/ˈbætəri/

noun … “Device that stores chemical energy and provides electrical power.”

Battery is a portable energy source that converts stored chemical energy into electrical energy through electrochemical reactions. Batteries provide direct current (DC) electricity, powering devices ranging from small electronics like smartphones and watches to large systems like electric vehicles and backup power grids. They consist of one or more electrochemical cells, each containing electrodes (anode and cathode) and an electrolyte that facilitates ion flow.

Key characteristics of Battery include:

• Voltage: electrical potential difference across its terminals.
• Capacity: measured in ampere-hours (Ah), representing how much charge it can store.
• Energy density: amount of energy stored per unit weight or volume.
• Rechargeability: primary (non-rechargeable) vs. secondary (rechargeable) batteries.
• Internal resistance: affects efficiency and power delivery.

Common types of Battery include alkaline, lithium-ion, lead-acid, nickel-metal hydride (NiMH), and solid-state batteries. Batteries are used in consumer electronics, electric vehicles, renewable energy storage, medical devices, and backup power systems.

Workflow example: Supplying power to a circuit:

battery_voltage = 9
circuit.connect(battery_voltage)
device.power(circuit.output)

Here, the battery provides DC voltage to power the device through the connected circuit.

Conceptually, a Battery is like a water tank storing energy: it holds potential energy and releases it when needed to keep the system running.

See DC, Power Supply, Energy Storage, Voltage, Current.