Como se projeta um cabo USB-Y?
Ele é projetado para dispositivos que exigem mais potência do que a disponível em uma única porta USB.
Whereas from the third test, it shows the male plug attached to thin cable doesn't carry enough power or usb data
Este conector extra não possui linhas de dados (D-, D +); só tem as linhas de energia (GND, VBUS).
Todos os três plugues devem estar conectados à energia e dados USB?
Sim. Os dois conectores na extremidade Y devem ser conectados ao PC / Laptop e a outra extremidade ao seu dispositivo USB.
Quero verificar se o cabo está com defeito.
First, I connected two male plug ends to laptop and third male plug to disk, it works fine.
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É assim que o cabo deve ser usado para que não seja defeituoso
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Os outros testes estão usando o cabo de maneira que não devem ser usados, então os testes não têm sentido.
Quais são os dois tipos diferentes de cabos Y?
One male connector, two female connectors
There are two types of the one male two female cables. One is a basic charging cable, splitting one port's power across two devices. The other is a specialised cable that somehow splits the data lines - and it's only used in very specific applications.
Two male connectors, one male or one female connector
What happens is you have your USB cable, one side for the host and one for the device, but with an extra connector attached. This extra connector does not have any data lines (D-, D+); it only has the power lines (GND, VBUS). It's attached in parallel to the existing cable. In other words, VBUS is connected to VBUS and GND is connected to GND.
Fonte Posso conectar com segurança a extremidade somente de energia de um cabo USB-Y a outra fonte de alimentação? responder por Bob )
Requisitos de energia
Some devices, such as high-speed external disk drives, require more than 500 mA of current[89] and therefore may have power issues if powered from just one USB 2.0 port: erratic function, failure to function, or overloading/damaging the port.
Such devices may come with an external power source or a Y-shaped cable that has two USB connectors (one for power and data, the other for power only) to plug into a computer. With such a cable, a device can draw power from two USB ports simultaneously.However, USB compliance specification states that "use of a 'Y' cable (a cable with two A-plugs) is prohibited on any USB peripheral", meaning that "if a USB peripheral requires more power than allowed by the USB specification to which it is designed, then it must be self-powered."
Fonte USB