James

The AC loop and the DC loop of a rectifier stage are two antennas, and their size is entirely under the designer’s control. A layout that keeps the loops small stays quiet; one that lets them grow radiates switching noise the components never intended. This article frames the loop-as-antenna idea, shows the trace, via, and … Read more

The 1N4728A is a 3.3 V Zener diode that a buyer and a repair bench read in two completely different ways. The buyer sees a part number, a voltage rating, and a price; the bench sees a curve to measure, a breakdown knee to find, and a part to verify before trusting it. Both workflows … Read more

An ATX power supply is the most common power electronics board most people will ever open, and it is also the one most often misdiagnosed. From wall plug to 12 V rail, the board walks through a defined chain — input bridge, PFC, rectification, down-conversion — and each step has a diode with a job … Read more

The stored charge in a diode junction is a time bomb that releases every time the diode turns off. In an SMPS switching at high frequency, that release happens thousands of times per second, and each release sends a current overshoot back into the inductor — a spike that heats, stresses neighbors, and radiates EMI … Read more

Every SMPS has an output rectifier, and every output rectifier is a choice between three technologies that hide different loss envelopes. A fast-recovery diode, a Schottky, and a synchronous-rectifier MOSFET can all be the “right” answer depending on the output voltage, the switching frequency, and the loss split of the specific converter. This article pairs … Read more

A switching power supply looks like a box of unrelated parts until you see the jobs. Five component types — the switch, the transformer, the rectifier diode, the output capacitor, and the controller — carry the whole conversion, and each one is a worker with a specific job whose failure has a specific signature. When … Read more

One trades heat for noise. That sentence is the whole story of linear versus switching power supplies, because every difference between the two topologies traces back to whether they convert the line power with a switching element or without one. A linear supply is simple, quiet, and inefficient — most of the wasted energy leaves … Read more

There are three ways to make a 5 V rail from a higher supply, and they are not equivalent. A Zener shunt is simple and cheap but wastes power as soon as the load is small; a linear LDO is cleaner but burns the same drop as heat; a buck DC-DC is efficient but adds … Read more

Every switch cycle in a flyback converter ends the same way: the switch turns off, the leakage energy in the transformer releases, and the output rectifier rings like a struck bell. The spike and the oscillation have a rhythm you can measure on a scope, and the snubber is the tuning that damps it. This … Read more

The gate oxide of a MOSFET is a door roughly 20 nanometers thick, and spikes and ringing can break it. A gate driven past its voltage limit, or hit by a fast dv/dt spike, fails the part in an instant — and the Zener clamp is the doorstop that holds the door. This article explains … Read more

Repairing a power supply is not a parts-drawer exercise; it is a sequence, and the sequence starts with safety. The order of actions — discharge, isolate, limit, test — is what separates a safe repair from a dangerous one and a quick diagnosis from a parts swap that fails again. This article builds the safety-first … Read more

A rectifier-based power stage fails in the field for a small set of reasons, and the reasons are nearly all visible before the board ships. The ten-check audit turns that knowledge into a release gate: ten questions, each with a pass criterion and a trace to the design method that answers it. This article presents … Read more