🧲 Neodymium magnets
caution
Where you meet it: HDD actuator magnet stacks, speaker assemblies, motors
What you need to know
- HDD magnet plates pinch hard enough to break fingers. Slide them apart sideways rather than pulling them straight off.
- Keep them away from pacemakers, credit cards, phones and mechanical watches.
- They shatter into sharp fragments when they slam together — eye protection.
The rule: Don't let two magnet plates snap together across your fingers.
Components this applies to
Ceramic CCD/CIS Image Sensors
Au 0.02–0.15 g per ceramic package ≈ 1.8 g/lbAu under 0.001 g per mobile/webcam moduleBase Nd-Fe-B in VCM actuators
A
HDD head arms & actuator assemblies
Au 0.1–0.3 g/lbNd NdFeB magnetsCu voice coil
C
Klystrons & Travelling-Wave Tubes
Cu ~250 g/lb (0.35–0.75 lb Cu per lb of tube)Au ~0.5–4 g per tubeAg 2–30 g per tube
C
MAF, MAP, knock, crank & cam sensors
Pt 0.5–2 mg per hot-wire MAFAu 0.003–0.010 g per MAF boardAg 10–40 mg thick-film paste on MAP hybridsNd magnets in Hall-type crank/cam sensors
D
Optical Drives & Laser Pickups
Au 0.01–0.03 g per drive ≈ 0.011 g/lbCu ~16 g/lbBase Al 200–400 g
D
Tape Drives & Libraries (LTO/DLT/DAT)
Au 0.05–0.20 g per LTO drive ≈ 0.03 g/lbCu ~10 g/lbBase 0.7–1.8 kg aluminium per full-height drive
D
Transformers, inductors, chokes & toroids
Cu 100–220 g/lb
D