The relay switch box usb can work without a power supply as it is connected and powered via just a 5v usb port.
Relay switch box usb.
17 32 of 604 results for usb controlled relay arceli srd 05vdc sl c 1 way 5v relay module free driver usb control switch pc intelligent control 5v 1 channel 4 2 out of 5 stars 17.
Use 1 mux chip and two of the power switch ics and you will not require any relays or relay coil drives and catch diodes.
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2 channel micro usb relay module is equipped with a stable usb to serial port chip and a microcontroller.
It can use the serial port debugging software to send serial commands on the computer to control the opening and closing of the 2 channel relay.
Numato s 1 channel usb powered relay module provides exceptional value for money.
It has one onboard 5v dc relays that can switch up to 2a load.
Endgroup michael karas feb 28 16 at 15 12.