Other · Tier D

Thermistors (NTC/PTC) and piezo elements

A 10 µm fired silver layer on a ceramic disc is around half a percent of the part's weight. Real silver, trivially little of it.

Ag 2–5 g/lb

eBay typical$20–70per lb

Refiner pays$2per lb

Metal in it$5.70per lb at 4 Aug 2026 spot

Confidencelowof the yield figures

How to spot it

NTC inrush thermistors are fat black or dark-blue discs, 5–20 mm, marked 5D-9 or SL22, in series with the mains inlet. PTC types are flat blue or grey discs in degauss and motor-start circuits. Piezo elements are thin brass discs with a grey ceramic patch and one or two solder wires.

Metal content

Metal	Quantity	Notes
Silver	2–5 g/lb	calculated from a ~10 µm fired Ag electrode at 70–75% Ag paste on a thin ceramic disc

At 4 Aug 2026 spot prices that works out to $5.70 per pound of contained metal — Silver 3 g = $5.70. A refiner paying $2 returns about 35% of that, which is normal: refining costs money and the buyer takes a margin.

Safe removal

Working temperature: Snip leads; burn coating 400–500 °C

Snip leads at the board. For piezos, peel the ceramic patch off the brass diaphragm — the brass is worth more clean. PZT ceramic is over 60% lead oxide by weight: never grind it dry and keep the dust away from food and skin.

Hazards

☠ Lead — dust more than fume

NEVER dry sweep or use compressed air on a scrapping bench. HEPA-vac or wet-wipe only.

🪚 Fibreglass and board dust

NEVER dry-cut boards indoors without extraction.

💨 Fumes, ventilation and open flame

NEVER burn boards, wire insulation or plastic. Ever.

Before you scrap it

Piezo discs and buzzers sell $0.30–1.50 each to makers, and specific NTC inrush parts are always needed for PSU repair — a sorted pound clears $25–70.

The common trap

Both look silvery and hint at metal, but the electrode is a fired paste microns thick. A whole pound is under $6 of silver.

Questions

How much gold is in thermistors (ntc/ptc) and piezo elements?

Silver: 2–5 g/lb. At current spot that is about $5.70 of contained metal per pound.

How do you identify thermistors (ntc/ptc) and piezo elements?

A 10 µm fired silver layer on a ceramic disc is around half a percent of the part's weight. Real silver, trivially little of it.

How do you remove thermistors (ntc/ptc) and piezo elements safely?

Snip leads at the board. For piezos, peel the ceramic patch off the brass diaphragm — the brass is worth more clean. PZT ceramic is over 60% lead oxide by weight : never grind it dry and keep the dust away from food and skin.

Is thermistors (ntc/ptc) and piezo elements worth more working than as scrap?

Piezo discs and buzzers sell $0.30–1.50 each to makers, and specific NTC inrush parts are always needed for PSU repair — a sorted pound clears $25–70.

Related in Other

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