A coupling capacitor, also known as a blocking capacitor, is a capacitor used to connect two circuits or devices while blocking the flow of direct current (DC) and allowing the passage of alternating current (AC). It is typically used to couple the output of one stage of an amplifier to the input of the next stage, or to couple the output of a signal source to the input of an amplifier.
Choosing the right coupling capacitor is important to ensure that the circuit operates correctly. The capacitance of the capacitor should be large enough to allow the AC signal to pass with minimal attenuation, but small enough to prevent the DC voltage from affecting the next stage. The voltage rating of the capacitor should be high enough to withstand the maximum voltage that will be applied to it.
