I need to measure voltage up to 30V with PIC18F1320 microcontroller. I am going to use divider with to resistors R1 and R2. So maximum input voltage to microcontroller wil be 5V. But microcontroller datasheet says that: The maximum recommended impedance for analog sources is 2.5 kOhm. So how to calculate resistor chain impedance; maybe it will be 2,5k o maybe sum of R1 and R2, that is 15kOhm?
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