Editing 2317: Pinouts
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| +240V DC | | +240V DC | ||
| This is a reference to heavy-duty home and commercial appliances, which use 240V AC for power. Additionally, many cable specifications try to provide a way to power devices over them (PS/2, USB, Power over Ethernet,) but these small communication cables usually carry only DC and not AC electricity. | | This is a reference to heavy-duty home and commercial appliances, which use 240V AC for power. Additionally, many cable specifications try to provide a way to power devices over them (PS/2, USB, Power over Ethernet,) but these small communication cables usually carry only DC and not AC electricity. | ||
− | High voltage power is only sometimes used in small communications connectors. It might help to keep the current of power lines low to avoid generating excess heat. With +240V DC inside the HDMI cable, monitors would not need any longer a separate power plug. This is similar to Power-over-Ethernet, which does not exceed 60V, or ISDN, which goes up to 110V depending on country, and helps surveillance cameras or telephones to work with one connecting cable only. But with this much voltage on such a small cable, a short could lead more likely to melting the insulation and wiring in a sudden burst of toxic smoke. The produced thermal power through a short with resistance | + | High voltage power is only sometimes used in small communications connectors. It might help to keep the current of power lines low to avoid generating excess heat. With +240V DC inside the HDMI cable, monitors would not need any longer a separate power plug. This is similar to Power-over-Ethernet, which does not exceed 60V, or ISDN, which goes up to 110V depending on country, and helps surveillance cameras or telephones to work with one connecting cable only. But with this much voltage on such a small cable, a short could lead more likely to melting the insulation and wiring in a sudden burst of toxic smoke. The produced thermal power through a short with resistance R that is building up is U²/R, increasing with the square of the voltage. However, a high voltage reduces the chance of a peripheral drawing too much current, which could cause a fire on thin wires otherwise: The current for a device, needing a power of P, is I = P_dev/U, the thermal power of the cables with resistance R is P_cables = I²*R = P_dev*R/U², so it is reduced by the square of the voltage. |
| 13 | | 13 | ||
| CEC | | CEC |