low pass filter

A simple passive RC Low Pass Filter or LPF, can be easily made by connecting together in series a single Resistor with a single Capacitor . In this type of filter arrangement the input signal ( Vin ) is applied to the series combination (both the Resistor and Capacitor together) but the output signal ( Vout ) is taken across the capacitor only. This type of filter is known generally as a “first-order filter” or “one-pole filter”, why first-order or single-pole?, because it has only “one” reactive component, the capacitor, in the circuit.