The Only Two Things That Create Voltage Spikes

Описание: If your board randomly resets, glitches, or behaves intermittently, there’s a very good chance this equation is involved:

V = L · di/dt

There’s nothing exotic about it. We all learned it in Circuits 1.

But most engineers don’t intentionally design around both sides of it.

In this video, I use a simple LED + MOSFET circuit to demonstrate:

• How parasitic inductance (L) causes large voltage droop
• Why fast switching edges (di/dt) make it worse
• How gate resistors reduce microcontroller stress
• Why “it works most of the time” is not good enough
• How 1% edge cases become long-term production headaches

You’ll see:

A microcontroller pin exceeding safe current

VGS operating right at threshold margins

Intermittent behavior that would only show up on a small percentage of boards

How shortening the loop with proper decoupling dramatically reduces the spike

This is the kind of issue that can live inside a company for years — quietly patched by technicians — until someone finally decides to fix it properly.

The absence of failure does not mean the design is correct.

Next video: we scale this up to ~6 amps and look at soft start behavior in a real power scenario.