Page review information

Edition covered

Established electrical theory — no single governing standard — n/a — textbook-level theory module

Content status

Reviewed

Coverage

Training module: Passive Components: Resistors and Capacitors — educational treatment; verify design decisions against the governing standards.

Last reviewed

August 2026

Primary reference

The official published standard — required for final decisions

Confirm the governing edition, jurisdiction, and project-specific requirements before applying anything on this page.

Training — Electrical Fundamentals

Passive Components: Resistors and Capacitors

Beginner Time: 20 min Type: Concept Focus: Controls / Panel Design

After this module: Understand resistors, capacitors, and inductors — their ratings, stored energy, and behavior in DC and AC circuits.

Prerequisites: Electrical Quantities and Circuit Language

Purpose

This module explains the basic practical behavior of two common passive components used throughout electrical and control work.

Resistors

Resistors are used to:

• limit current
• create intentional voltage drop
• bias signals
• form dividers and timing networks

Key practical checks:

• resistance value
• power rating
• tolerance
• heat generated in use

Capacitors

Capacitors store charge between two conductors separated by an insulating dielectric.

Common uses:

• smoothing and filtering
• timing
• energy storage
• noise suppression

Component families

Common resistor families:

• carbon or film types
• metal film
• wire-wound

Common capacitor families:

• ceramic
• film
• electrolytic

Different families trade size, stability, voltage capability, and failure mode differently.

Practical cautions

• Electrolytic capacitors are polarity-sensitive.
• Capacitors can hold hazardous stored energy after power is removed.
• Resistors fail from heat as often as from wrong resistance value.
• Real components are not ideal; tolerance and temperature matter.

Working takeaway

For both parts, value alone is not enough. Always check:

• the electrical job
• the physical part family
• the rating
• the failure consequence

Related standards

• NFPA 79-2024, Chapter 7 — Protection against electric shock
• IEC 60204-1:2016+AMD1:2021, Clause 6 — Protection against electric shock

---

← Electrical Equations Reference ↑ Electrical Fundamentals Diodes, Transistors, and Switching Basics →

Trust Boundary — Engineering Judgment Required

This site is an independent educational reference for industrial automation standards. It paraphrases and organizes guidance in original language; it is not a substitute for the official published standards, professional engineering judgment, or legal review, and content has not been independently verified against current published editions.

Items marked Review pending await technical review against the identified edition. Items marked Planned have no reviewed source material behind them. Do not rely on this site for compliance determinations, safety-critical design decisions, or legal interpretation.