Comments: Voltage Dividers

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  • If anyone needs a very useful voltage divider calculator, here’s one that searches through actual resistor values to find the best match for your Vin / Vout, then tells you what the min/max voltage will be based on the resistor tolerances. :-)

    Voltage Divider Calculator

  • The Voltage divider tutorial is VERY helpful and straight forward. But as I plan to use one to divide 5 volts down to 3.3 as done in your example, I am concerned that my calculations do not include the resistance (impedance) of the device being connected across R2. In the case of the GPIO of a Raspberry Pi or in the accelerometer case, when I connect the input of this across R2, might if significantly change the effective resistance of R2 and thus the amount of voltage across it? How can I know the impedance of devices such as what I mentioned? Many thanks.

    • For most components that would most likely be listed in the data sheet. If it’s not then the worst case scenario is using a volt meter to measure the actual resistance.

  • Hi! Are there any tutorials for voltage dividing for power supplies? It explicitly says here not to use this circuit for power supplies, so it would be good to see how that is done!

  • All sparkfun tutorials are awesome, wish they will make one for op-amps

  • Thanks for refreshing my knowledges. Please write post about “Voltage doubling”.


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