L, symbol for inductance | Magnetic fields and inductance |

L1, "hot" wire designation | "Ladder" Diagrams |

L2, "neutral" wire designation | "Ladder" Diagrams |

Ladder circuit / logic gate equivalents | Digital logic functions |

Lagging phase shift | AC Phase |

| Calculating Power Factor |

laminated core | Hysteresis and Eddy Current |

laminated iron core | Energy losses |

Laser diode | Laser diodes |

latch vs. flip-flop | Edge-triggered latches: Flip-Flops |

Latch, D | The D latch |

Latch, gated S-R | The gated S-R latch |

Latch, S-R | The S-R latch |

Latch-up | Common-Mode Gain |

| High-impedance voltmeter |

Latched state | NOR gate S-R latch |

latching | The Shockley Diode |

Law of cosines | Trigonometry Reference |

Law of sines | Trigonometry Reference |

LC resonance | Simple parallel (tank circuit) resonance |

Lead, test | Safe meter usage |

lead-acid battery | Electron activity in chemical reactions |

| Practical considerations |

Leading phase shift | AC Phase |

| Calculating Power Factor |

leakage current | Diode ratings |

| Diode Characteristic |

leakage inductance | Mutual inductance and basic operation |

| Stray capacitance and inductance |

leakage, capacitor | Electric fields and capacitance |

LED | Voltmeter usage |

| AND gate |

| Light-emitting diodes |

LED flasher | Long Duration Minimum Parts Red LED Flasher |

| Long Duration Blue LED Flasher |

| Long Duration Flyback LED Flasher |

| Long Duration Red LED Flasher |

LED sequencer | LED sequencer |

Left-hand rule | Electromagnetism |

Lenz's Law | Inductors and calculus |

| AC Inductor Circuits |

level switch | Switch types |

Light Emitting Diode | AND gate |

light-emitting diode | Voltmeter usage |

| Light-emitting diodes |

lightning | Nonlinear Conduction |

limit switch | Switch types |

Limits, calculus | Calculus Reference |

line decoder | Decoder |

| Demultiplexers |

| Multiplexers |

Line, polyphase system | Three-Phase Y and Delta Configurations |

linear | Nonlinear Conduction |

linear induction motor | Linear induction motor |

linear taper potentiometer | Sensitive audio detector |

| Potentiometer as a Voltage Divider |

| Sensitive voltage detector |

Linearit | Strain gauges |

Lissajous figure | Frequency and Phase Measurement |

Litmus strip | pH measurement |

Litz wire | Inductor quirks |

load | Resistors |

Load, nonlinear | Power quality measurement |

Loading, voltmeter | Voltmeter impact on measured circuit |

Lock-out/Tag-out | Safe practices |

Lodestone | Permanent magnets |

Logarithm | Algebra Reference |

Logarithm, common | pH measurement |

Logarithm, natural | Solving for unknown time |

Logarithmic scale | Ohmmeter design |

Logic gate / ladder circuit equivalents | Digital logic functions |

logic gate shape symbols | Shift Register, Parallel-in, Serial-out |

Logic level | Digital signals and gates |

logic simplification | Introduction |

Logic, Aristotelian | Introduction |

Logic, fuzzy | Introduction |

Look-up table | Look-up tables |

Loom, Jacquard | Memory with moving parts: "Drives" |

Loop antenna | Principles of radio |

loss | Decibels |

Low, logic level | Digital signals and gates |

low-pass filter | Low-Pass Filters |

LSB | Decimal versus binary numeration |

LVDT | AC Instrumentation Transducers |