Cesium oven and smart meter: what they have in common

1. Step 1. Cesium oven — is part of — Atomic clock. A source of the atomic beam.
2. Step 2. Atomic clock — is used in — GPS (satellite navigation). The satellites carry atomic clocks; the position is calculated from signal arrival times.
3. Step 3. GPS (satellite navigation) — is used in — Car navigator. GPS.
4. Step 4. Car navigator — has part — Liquid-crystal display. A screen.
5. Step 5. Liquid-crystal display — is part of — Smart meter. A display.

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