A PERSONAL ENGINEERING JOURNAL

From a sketch
to a working board.

I build small devices, draw boards and write firmware. These are my bench notes: what worked, what failed, and what I changed in the next revision.

01 /Latest bench notes

The trigger showed the right voltage, yet the attached board kept restarting. I enabled the load before the supply settled.

It worked on the bench but restarted inside the case. The return path of the relay current was the part I had overlooked.

With a 10 mΩ shunt, readings still depended on where I soldered the wire. The missing resistance was on the PCB.

I put the LED driver on a resistive load and watched the temperature. A closed enclosure needed a lower current limit.