Description: Transistors are used as amplifiers or switches, where a small current at one terminal is used to control a much larger current at another terminal.

Uses: Transistors are very commonly used in just about any electronics product or application.

Also known as: Rectifier

Description: Diodes conduct electricity in one direction only.

Uses: Diodes are very commonly used in just about any electronics product or application. They are used to protect against making connections with incorrect polarity and in voltage rectifiers that turn AC current into DC current.

Description: Capacitors store an electrical charge. Capacitance is measured in farads, or more commonly, microfarads.

Uses: Capacitors are very commonly used in just about any electronics product or application. They are commonly used for signal filtering, suppression of electrical noise, and in oscillators.

Description: Resistors resist the flow of an electrical current. Resistance is measured in ohms. A potential difference of one volt will force a current of one ampere through a resistance of one ohm.

Uses: Resistors are very commonly used in just about any electronics product or application. Common resistors of the type pictured are typically rated to handle 1/8, 1/4, or 1/2 watt.