# @stem_antics on Instagram

- **Type:** Video
- **Original URL:** https://www.instagram.com/p/Da8K70eAAq4
- **Gondola URL:** https://gondola.cc/posts/67970781-stem-antics-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/fbcc0bc01a.jpg
- **Posted:** 2026-07-18T16:02:12.000+00:00
- **Account Owner:** Stem Antics (@stem_antics) — https://gondola.cc/stem_antics

## Caption

A one is not a one. It is a voltage.

At the bottom of every computation sits a slab of silicon and a decision about electricity. Binary exists because transistors are excellent at two things and terrible at everything in between: fully on, fully off. Ask a transistor to hold a precise intermediate value and thermal noise, manufacturing variation and supply ripple will corrupt it within microseconds. Ask it to sit at 0 V or 0.8 V and it will hold that state against considerable abuse.

The workhorse is the MOSFET. Three terminals plus the body:

- Gate, insulated from everything by a few nanometres of oxide
- Source and drain, two doped regions in the substrate
- The channel between them, which conducts only when the gate says so

Put a positive voltage on the gate of an NMOS device and the field pulls electrons toward the surface, inverting the region beneath the oxide into a conducting channel. Below the threshold voltage, no channel, no current. Above it, current flows. That threshold is the entire basis of digital logic: a continuous physical process forced into a step function.

CMOS pairs each NMOS with a complementary PMOS so that one is always off. An inverter is two transistors: input high pulls the output to ground, input low pulls it to the supply. Static current is nearly zero, which is why a chip with fifty billion transistors does not immediately melt. Power is burned during switching, charging and discharging parasitic capacitance, which is why clock speed and heat are inseparable.

Noise margin is the quiet hero. Anything below roughly 0.2 of the supply reads as zero, anything above 0.8 reads as one, and the forbidden zone between them is where signals are not allowed to linger. Every gate restores the signal it receives, so error does not accumulate across a billion stages.

Binary is not a mathematical preference. It is what survives the physics.

#stemantics #electronics #semiconductors #electricalengineering #physics

## Stats

- **Views:** 4,008
- **Likes:** 63
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## Tags

electronics, semiconductors, physics, electricalengineering, stemantics

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