The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

The New Hotness

  • Tour Easy: Amber DRL Internal Resistor

    Plotting current against voltage for the amber truck side marker lights produces the expected straight-ish line:

    Side Marker I vs V plot - with fuse
    Side Marker I vs V plot – with fuse

    The slope suggests a 330 Ω resistor, but the internal PCB sports a pair of 150 Ω SMD resistors.

    I don’t believe the X-axis intercept for a moment, but 1.5 V seems about right for an amber LED.

    Oh, and the DMM fuse doesn’t have a ceramic body. You’re seeing the vaporized remains of a 315 mA fuse neatly deposited over the inside of the glass tube after being shorted across a 3 A bench supply.

    I hate it when that happens. Replacing it emptied the little bag of those meter fuses; next time it’ll get a half amp fuse.