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# Capacitor charge in an RC circuit

In order to study the behavior of an RC circuit, I connected a resistor and a capacitor to an Arduino's I/O as shown:

The Arduino digital Output feeds the circuit with a square pulse of 2 sec duration. (one second HIGH, one second LOW)

for a charge time of 1 sec: $$V_c = E(1-e^{-\dfrac{t}{\tau}}) = E(1-e^{-\dfrac{1}{0.83}})=0.7E$$

where E is the power supply voltage

Converting E value to a 10bit range, $$V_c = 0.7 \times 1024 = 717$$