REFERENCE

Electrical reference

Units, components, circuit symbols and common electrical laws.

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Quantity / concept	Unit / formula	Meaning
Voltage	V	Potential energy per unit charge: 1 V = 1 J/C.
Current	A	Rate of charge flow: I = dQ/dt; 1 A = 1 C/s.
Resistance	Ω	For an ohmic device, R = V/I.
Power	W	Rate of energy transfer: 1 W = 1 J/s. DC power P = VI.
Charge	C	Electric charge; one elementary charge is exactly 1.602176634×10⁻¹⁹ C.
Efficiency	%	Efficiency = useful output power / input power × 100.
Power factor	ratio	PF = real power / apparent power. A balanced sinusoidal load has PF = cos φ.
Capacitance	F	C = Q/V. A capacitor stores E = ½CV².
Inductance	H	An ideal inductor satisfies v = L di/dt and stores E = ½LI².
Apparent power	VA	For single-phase AC: S = V_rms I_rms.
Kilowatt	kW	1 kW = 1,000 W.
Kilowatt-hour	kWh	1 kWh = 3,600,000 J; it is energy, not power.
Decibel	dB	Power ratio: 10 log₁₀(P₂/P₁). Amplitude: 20 log₁₀(A₂/A₁) for equal impedances.
dBm	dBm	Absolute logarithmic power referenced to 1 milliwatt.
dBW	dBW	Absolute logarithmic power referenced to 1 watt.
Resistor	R	An ideal resistor dissipates electrical energy: P = I²R.
Capacitor	C	Opposes a change in voltage; ideal impedance is 1/(jωC).
Inductor	L	Opposes a change in current; ideal impedance is jωL.
DIP switch	switch	A set of manually operated switches packaged together for configuration.
Solder bridge	jumper	A conductive solder connection joining adjacent pads. Inspect the intended circuit before changing it.
Ohm’s law	V = IR	Applies to an ideal ohmic resistance under the stated physical conditions.
Voltage divider	Vout = Vin R₂/(R₁+R₂)	Unloaded series resistors; an output load changes the equivalent lower resistance.
Kirchhoff current law	Σ I = 0	Algebraic currents at a node sum to zero under the lumped-circuit model.
Kirchhoff voltage law	Σ V = 0	Algebraic voltage rises and drops around a closed loop sum to zero in a lumped model.
Coulomb’s law	F = k \|q₁q₂\|/r²	Point charges in vacuum, k ≈ 8.9875517923×10⁹ N·m²/C².
Energy saving	E = P × t	Compare measured power and operating hours; use kWh with your actual tariff.

Common circuit symbols

These are educational circuit relationships. Wire geometry, schematic symbols, and ideal laws do not establish component or installation ratings.

Reference tables are generated locally. Unicode display depends on your installed fonts; unassigned code points may have no visible glyph.

THE QUICK START

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01
Browse the reference table or choose a reference section.
02
Filter entries or change the Unicode starting point or table size.
03
Read the symbols and definitions alongside their stated limitations.

A LITTLE CONTEXT

About this tool

Units, components, circuit symbols and common electrical laws. Reference entries and numeric tables are generated locally, with no remote document or account required.

Unicode glyphs depend on installed fonts. Math and electrical entries are educational references, not installation ratings or professional design specifications.

GOOD TO KNOW

A couple of useful answers.

How do I use electrical reference?+

Browse the reference table or choose a reference section. Filter entries or change the Unicode starting point or table size. Read the symbols and definitions alongside their stated limitations.

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Files and tool inputs are processed on your device. Media access starts only after your action and browser permission.

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Quantity / concept

Unit / formula

Meaning

Voltage

Potential energy per unit charge: 1 V = 1 J/C.

Current

Rate of charge flow: I = dQ/dt; 1 A = 1 C/s.

Resistance

For an ohmic device, R = V/I.

Power

Rate of energy transfer: 1 W = 1 J/s. DC power P = VI.

Charge

Electric charge; one elementary charge is exactly 1.602176634×10⁻¹⁹ C.

Efficiency

Efficiency = useful output power / input power × 100.

Power factor

ratio

PF = real power / apparent power. A balanced sinusoidal load has PF = cos φ.

Capacitance

C = Q/V. A capacitor stores E = ½CV².

Inductance

An ideal inductor satisfies v = L di/dt and stores E = ½LI².

Apparent power

For single-phase AC: S = V_rms I_rms.

Kilowatt

1 kW = 1,000 W.

Kilowatt-hour

kWh

1 kWh = 3,600,000 J; it is energy, not power.

Decibel

Power ratio: 10 log₁₀(P₂/P₁). Amplitude: 20 log₁₀(A₂/A₁) for equal impedances.

dBm

Absolute logarithmic power referenced to 1 milliwatt.

dBW

Absolute logarithmic power referenced to 1 watt.

Resistor

An ideal resistor dissipates electrical energy: P = I²R.

Capacitor

Opposes a change in voltage; ideal impedance is 1/(jωC).

Inductor

Opposes a change in current; ideal impedance is jωL.

DIP switch

switch

A set of manually operated switches packaged together for configuration.

Solder bridge

jumper

A conductive solder connection joining adjacent pads. Inspect the intended circuit before changing it.

Ohm’s law

V = IR

Applies to an ideal ohmic resistance under the stated physical conditions.

Voltage divider

Vout = Vin R₂/(R₁+R₂)

Unloaded series resistors; an output load changes the equivalent lower resistance.

Kirchhoff current law

Σ I = 0

Algebraic currents at a node sum to zero under the lumped-circuit model.

Kirchhoff voltage law

Σ V = 0

Algebraic voltage rises and drops around a closed loop sum to zero in a lumped model.

Coulomb’s law

F = k |q₁q₂|/r²

Point charges in vacuum, k ≈ 8.9875517923×10⁹ N·m²/C².

Energy saving

E = P × t

Compare measured power and operating hours; use kWh with your actual tariff.

Common circuit symbols

These are educational circuit relationships. Wire geometry, schematic symbols, and ideal laws do not establish component or installation ratings.

Reference tables are generated locally. Unicode display depends on your installed fonts; unassigned code points may have no visible glyph.

Common circuit symbols

One less thing on your list.

About this tool

A couple of useful answers.

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