-5

How to measure voltage at micro usb port on android with multimeter???I connected black wire to the ground pin and red wire to VBUS but is not showing anything on display. Connector is connected to Micro B port and Micro B connector is on the cable end.

Pavle
  • 1
  • 3
  • 1
    Is there a reason to ask this again? Without really clarifying anything? Duplicate of 206105. And, assuming that you have the cable plugged into the phone, and are measuring the other end, your phone isn't a current source... it is a consumer. – R Drast Dec 15 '15 at 18:06
  • Android is an OS. Presumably you mean a piece of hardware running Android, what is it? – Leon Heller Dec 15 '15 at 18:41

1 Answers1

0

Normal cell phone or tablet usb ports will not output a voltage on the usb VUSB/VCC or GND pins. OTG usb ports, if supported by the phone, need to be enabled by grounding the ID or Sense pin, before it will attempt to output 5V on the VUSB line.

enter image description here

A USB OTG adapter cable is typically needed. As a test, I hooked up a OTG adapter cable and a non-enumerating usb voltage tester (Essentially a multimeter) to a Samsung Galaxy S4 and got 5.1V volts showing up.

Passerby
  • 72,580
  • 7
  • 90
  • 202
  • Even with OTG cable it will not be possible to check the voltage with a multimeter. OTG powers the slave device for a split second and cuts the power off if no attempts to enumerate were made. You'll need an oscilloscope to see that. – Dmitry Grigoryev Dec 15 '15 at 18:15
  • 1
    @DmitryGrigoryev source? – Passerby Dec 15 '15 at 18:16
  • I know that from experience with TI SoCs. I assume TI is following the USB spec. – Dmitry Grigoryev Dec 15 '15 at 18:19
  • 1
    @DmitryGrigoryev I just connected a OTG adapter and a non-enumerating usb voltage/amperage tester (USB Charge Doctor) with my Samsung phone, and it shows up 5.13V for several minutes now. – Passerby Dec 15 '15 at 18:22
  • That's entirely possible. Here's [my experience](http://electronics.stackexchange.com/questions/165806/how-to-configure-usb-otg-as-power-supply). Let me correct myself: "it **may** not be possible to see that with a multimeter". – Dmitry Grigoryev Dec 15 '15 at 18:28
  • The activation of the charge pump is usually under software control, typically at kernel level. Normally this responds to the mode pin but it could be written to consider other factors. – Chris Stratton Dec 15 '15 at 18:41
  • Only with OTG adapter and a non-enumerating usb voltage/amperage tester (USB Charge Doctor) ?????? – Pavle Dec 15 '15 at 19:41
  • Where can I buy usb charge doctor??? – Pavle Dec 15 '15 at 20:16
  • @Pavle the usb charge doctor is a generic usb voltage meter (Check eBay or google for `usb voltage meter`). Its literally the same thing as a multimeter you use to measure the voltage. There is nothing special about it other than being convenient to use. – Passerby Dec 15 '15 at 20:20
  • Why is no possible to see usb voltage with a multimeter??? – Pavle Dec 15 '15 at 20:27
  • S3 Neo otg voltage: 0.00 volts, S3 OTG VOLTAGE: 5.15 volts – Pavle Dec 16 '15 at 22:51
  • Does the Neo support otg? Samsung tends to skimp out on the bargain phones. – Passerby Dec 16 '15 at 23:25
  • S3 Neo supports otg with external power supply. – Pavle Dec 17 '15 at 08:31