Computer Part Comparison Platform | PCPartPicker - Free community platform to share custom builds and rate different motherboards, power supplies, cases, and more.

Circuit Design Program | KiCAD - Free electronic design automation (EDA) suite. Includes schematic design (theoretical diagram) and layout design (production drawing). Open source and sponsored by CERN. Excellent entry-point program for circuit board prototyping and production.

Electronic Parts Distributor | North America - Examples: Mouser and Digikey. Provides parametric search across millions of components.

Circuit Protection

Bare circuits are fragile, so they must be strengthened and protected at many levels.

Consider the circuit board, solder mask, conformal coating, assembly potting, and structural enclosure.

Consider the air gaps in the circuit board (ex. thru-holes), vapor permeability of materials in the circuit assembly, mounting strength of the assembly within the enclosure, and the penetration of foreign particles into the enclosure.


Discrete electrical parts are single element circuits like resistors, capacitors, inductors, and transistors.

Circuit Enclosures

Plastic. Common enclosure material. Low cost, light weight, ease of molding, excellent electrical insulation. Versatility for built-in hinges, locking tabs, auto-tapping screw mounts. Generally suited for indoor applications. Plastics are prone temperature; brittle in cold, warps in heat.

Sheet metal. Common industrial enclosure material. Durability, ease of interface panel production. Heavier than plastic, but has cost-effective abrasion and impact resistance across a wide temperature range. Holes and slots easily formed for installation of ports, buttons, switches.

Extruded metal. Common industrial enclosure material. Durability and rigidity. Often forms the frame of metal enclosures that combine the strength of extrusions with the versatility of sheet metal. Extrusions are strong, but the material usually limited to aluminum for saving weight.

Circuit Protection

Standoffs provide secure mounting and physical isolation between the circuit assembly and its enclosure.

Gaskets seal the enclosure that contains the circuit assembly. Form-in-place (FIP) gaskets are made by looping a continuous bead of sealing compound on the closure surface. [Video]

Conformal coating is a light layer of protective compound applied on the surface of a circuit assembly. [Video]

Potting is the complete or partial submersion of a circuit assembly with sealing compound. The compound may be injected within either a reusable open mold or the outer shell of the assembly. [Video]

Overmolding is the complete submersion of a circuit assembly with sealing compound injected within a closed, pressurized mold. [Video]

Circuit Labeling

Screen printing, also known as silk screening, is the process of drawing ink through a mesh to print text and images on plastics and metals. Screen printing involves thermal setting of the ink by oven heating. Quality screen printing sets sharp and flat to the surface and does not rub off easily. Screen printing is a popular method of inscribing labels and symbols on electronic enclosures. [Video]


Resistance, Capacitance, Inductance


Pulse Width Modulation (PWM)

Piezoelectric Effect