A projector labeled 8,000 lumens measured 251 lux while a 200 ANSI-lumen model hit 477 lux. What ANSI lumens actually measure, why plain lumen ratings cannot be compared, and how many lumens each screen size needs.
The cabin limit for power banks is 160Wh, roughly 43,000mAh. Since 20 April 2026 it is two units per passenger, and in-flight charging is banned. Here is the mAh-to-Wh maths behind it.
The wattage printed on a charger is a ceiling. USB PD fixes a maximum for each voltage step, going past 100W requires a separately certified 240W cable, and a 65W three-port charger drops its main port to 35W once every socket is in use.
U3 and V30 on the same card mean the same thing — 30 MB/s minimum write, written in two different standards. A 340 Mbps 4K stream needs 42.5 MB/s. Here is the class table and the bitrate math.
The 24-month value of Korea's 25% plan discount on an 89,000-won tariff is 534,000 won. If the handset subsidy on offer beats that, take the subsidy; if not, take the discount. Plus what changed when the handset law was repealed.
To run 4K 120Hz gaming, 8K or VRR you need HDMI 2.1 — and a certified Ultra High Speed cable. Bandwidth is 18Gbps versus 48Gbps. Here is the required bandwidth computed by resolution and refresh rate.
A 20,000mAh pack won't charge your phone four times. Here is the gap between labeled and usable capacity (Wh conversion, conversion loss), PD output per device, and airline limits, worked out in numbers.
For a foldable, folded thickness and weight are the first gate. The latest models reach 8.9mm and 215g folded, but the '4' in IP48 is not full dust protection. Here are the five lines to check on the spec sheet.
Even with the same "fast charging" label, actual speed depends on USB PD support, PPS notation, and wattage. This post covers reading PD voltage profiles, why Galaxy ultra-fast charging requires PPS, multi-port output distribution, and 5A cables — based on published specifications.
A 60W and a 240W USB-C cable are different products despite the same plug shape. Connector, power (PD), and data are separate spec layers — knowing this lets you filter by packaging in seconds. This post covers the e-marker threshold, charge-only cable data traps, and the right grade per use case.