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Power Supply Voltage

1471 Views - Created 25/09/2018

25/09/2018

Posted by:
phoneman

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I have stacked a single ADC on a RaspberryPi Zero W.

I am using a pressure sensor where the spec sheet shows Supply Voltage of 5V+-.25V.

I have two sensors that have quit working. Today when I check the voltage on the supply pins of the ADC my fluke meter shows 5.13V.

Is the ADC just passing through power from the PiZero and do you think the voltage is stable and within range of the presure sensor?

25/09/2018

Posted by:
andrew

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Location:
United Kingdom

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The 5V pin on the ADC is connected to the Raspberry Pis 5V GPIO pin so it will pass through the power from the Raspberry Pi. The stability of the voltage is dependent on the power supply you are using for the Raspberry Pi.

Basic switch-mode supplies like those often supplied with Raspberry Pi kits may fluctuate by a few millivolts when the CPU on the Raspberry Pi is under heavy loads so it is best to monitor the 5V pin with a multimeter to see if the voltage does change when you are using the Raspberry Pi.

If your sensor needs a very stable supply voltage then it may be worth using a separate power supply for the sensors. As long as the ground pins for the sensor power supply and the Raspberry Pi power supply are connected together the ADC Pi should be able to read the voltages coming from a separate power supply without any issue.

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