Stage 2 · Lesson 3 of 7
Voltage dividers
Two resistors in series across a voltage split it: the midpoint sits at Vout = Vin x R2 / (R1 + R2). You will use this to bring a higher voltage into range, for example measuring a 12 V battery with a 3.3 V (analogue to digital converter), or reading a 5 V signal on a 3.3 V pin.
Potentiometers and many resistive , such as and light-dependent resistors, are dividers too. Choose resistor values high enough not to waste battery, but not so high that the ADC input cannot read them accurately; tens of kilohms is a common middle ground.
Common trapusing a divider to power a module: as soon as the module draws current the output , because a divider is only for signals, not supplies.
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Resources for this stage
Start with
- BookFreeAll About Circuits Textbook
All About Circuits · Beginner
Free: read the DC volume chapters on Ohm's law, series and parallel circuits and dividers
Practise
Keep handy
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