Electrochemical Migration And Dendrite Growth On PCBs A board can pass every electrical test, be clean enough to satisfy a conductivity measurement, and still fail in the field because a metal filament grew across a gap that nobody was measuring. The filament is the visible result of electrochemical migration, a…

Phototransistor: Preparation, Placement and Process Control A phototransistor is a photodiode with a built in current gain, which makes it far easier to use than a plain photodiode and slower than one. The interface is a load resistor and often an amplifier, and the choice of that resistor sets the…

Datasheet: Preparation, Placement and Process Control A processor datasheet runs to hundreds of pages, and most of the board is decided by a few tables inside it. Reading it in a defined order turns a datasheet into a set of design decisions rather than a reference to search. Read the…

Nvr Mainboard: Preparation, Placement and Process Control A network video recorder is a computer whose workload is almost entirely video, and its board is designed around that fact. NVR mainboard design means balancing decode channels, storage bandwidth and display outputs against a power budget that has to hold for years.…

Charger Ic: Preparation, Placement and Process Control A switching charger is a small converter with a battery on its output, and its layout follows the same rules as any switching supply. Charger ic board layout decides the efficiency, the temperature and the electromagnetic behaviour of a part that runs whenever…

Surface Insulation Resistance Testing Methods Explained Insulation resistance between two conductors on a bare laminate is theoretically enormous. In practice it is limited by whatever is on the surface: flux residue, handling salts, moisture, or a coating that has not cured. Surface insulation resistance testing measures that surface condition electrically,…

PCB Thermal and Electrical Separation Design in High Power LED Lighting In high power LED lighting applications, the driving current of a single LED chip often reaches 350 mA to 1,500 mA or more. If junction temperature, or Tj, continuously exceeds 125 degrees Celsius, it will significantly accelerate lumen depreciation,…

Thermal Via: Key Checks Before Release A power device does not lose its heat to the air. It conducts it into the copper pad beneath it, and from there into the planes and the other side of the board, where a heatsink or an airflow can remove it. On a…

Gold Finger: Preparation, Placement and Process Control An edge connector uses the board itself as the plug. The contacts are copper fingers plated with a wear resistant metal, and they slide into a mating socket when the card is inserted. The finger geometry, the plating stack, and the bevel at…

Projector Mainboard: Key Checks Before Release A compact projector fits a display engine, a battery and a processor into a space the size of a book. Projector mainboard design is dominated by the light source, because the led driver and its power loop set the size, the heat and the…