Filter capacitors absorb and store electrical charges to remove voltage and signal spikes in electronic circuits. They are typically placed across a load or as a path to ground and come in different types such as electrolytic, ceramic, and tantalum. They are used to remove DC ripple, audio interference, and switch-induced arcing. Different types of filter capacitors are used for different applications, such as polarized electrolytic for power filtering and ceramic for RF filtering. They are widely used and remain one of the cheapest and most efficient methods of voltage filtering.
A filter capacitor is an electronic component that removes voltage or signal spikes in electronic circuits. Capacitors are used as filter devices due to their ability to effectively absorb and store electrical charges at predetermined values. This feature is used in a filter capacitor application to sink or buffer voltage values that exceed set parameters. Filter capacitors are typically placed across a load or as a path to ground in circuits. Different types of filter capacitors include electrolytic, ceramic and tantalum.
One of the many hurdles electronic circuit designers must overcome is the removal of voltage and signal anomalies. These can take the form of DC ripple in the power supply outputs, audio interference, and switch-induced arcing. These anomalies can wreak havoc especially in sensitive circuitry or high-end audio applications. A capacitor’s ability to absorb and hold electrical charges of known values makes it an ideal filter component for removing these voltage and signal spikes.
A filter capacitor is typically placed across a load or connected in such a way that it provides a controlled path to ground. In this configuration, the capacitor effectively sinks any voltage above its rating. The stored energy is either transferred to earth or dissipated back into the circuit at an appropriate point. The known operating range of the capacitors allows circuit designers to precisely match the filter capacitor to the circuit requirements.
The capacitors used for the DC power rail and power filtering are typically of the polarized electrolytic type. This type of capacitor offers high capacitance values in relatively small, cost-effective packages. Filter capacitors applied in radio frequency (RF) filtering applications remove signal interference in signal and power lines in radios and other audio equipment. These capacitors are usually of the ceramic or silver mica plate type with low inductance values.
Mains rated wound plastic film type filter capacitors are commonly used as arc suppressors. Ceramic disc capacitors are used on low voltage DC motors to filter out RF interference caused when the motor is running. Computers use many filter capacitors in their circuits with the tantalum capacitor being the most commonly used type. High-power crossover speaker systems use pairs of non-polarized electrolytic/ceramic capacitors to reduce signal interference. Indeed, few circuits do not employ a filter capacitor at some point and it remains one of the cheapest, most efficient and widely used methods of voltage filtering.
Protect your devices with Threat Protection by NordVPN
