IndexPanas & EntropiSticker

Nyquista

Johnson–Nyquist Noise / 4kTR Physics

$4.99 USD
$4.99 USD
Obral Habis
Size
Surface

Nyquista, a grinning goblin of the circuits, holds a striped resistor spitting jagged orange sparks.

The Physics

Any resistor at a temperature above absolute zero hisses with voltage noise, because its electrons jiggle thermally. John B. Johnson measured it at Bell Labs and Harry Nyquist explained it, both in 1928 (Phys. Rev. 32, 97 and 32, 110). The noise power per unit bandwidth depends only on temperature and resistance, not on the material.

⟨V²⟩ = 4kBTRΔf

  • ⟨V²⟩: mean-square noise voltage (V²)
  • kB: Boltzmann constant, exactly 1.380 649 × 10⁻²³ J/K since 2019
  • T: temperature (K)
  • R: resistance (Ω)
  • Δf: measurement bandwidth (Hz)

A 1 kΩ resistor at room temperature gives about 4 nV per √Hz. Because kB is now exact, Johnson noise can be used as a primary thermometer.

Honest caveat: The formula is the low-frequency limit; at very high frequency or low temperature quantum corrections (hf ≳ kBT) cut it off.

On the sticker

Nyquista holds a striped resistor with jagged orange lightning crackling from it. Printed text: NYQUISTA with the line 4kTR. Pixel-art kiss-cut vinyl sticker, white, in 2″, 3″, 4″ and 6″ sizes.

Shipping calculated at checkout by destinationMade to order, ships in 2–5 business days

Details

Size3″ × 3″

3″ × 3″ kiss-cut sticker.

Shipping

Shipping calculated at checkout by destination. Printed to order for you.

Delivery times & where we ship

Returns & replacements21 days

Every item is printed to order, so we can’t accept returns or exchanges for change of mind, or if you ordered the wrong size or colour.

Print defect, misprint, damage or the wrong item? We’ll send a free replacement, or a refund if you prefer. Report it within 21 days of delivery with a photo; no need to send it back.

Full refund & replacement policy

Field notes

Lihat semua
1 3
Lihat semua