Charging station and dewar flask: what they have in common

1. Step 1. Charging station — has part — Rectifier. Fast chargers rectify the mains current.
2. Step 2. Rectifier — is part of — LED lamp. The driver in the base rectifies mains current and limits the LED current; in an ordinary bulb it has no transformer.
3. Step 3. LED lamp — evolved from — Incandescent light bulb. It replaced incandescent bulbs.
4. Step 4. Incandescent light bulb — uses — Vacuum. The bulb was evacuated so the filament would not burn out.
5. Step 5. Vacuum — is used in — Dewar flask. A vacuum.

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