In a circuit like the one below, why is capacitor C1 needed? I mean I can make do with just a resistor and pot to attenuate the voltage to some level suitable for switching.
What does using capacitors add to the circuit, and what is it's advantages and disadvantages over just using simple resistors voltage dividers instead?
Also in the circuit in the 2nd graph I am not so sure what the purpose of adding C2 and R3.