Decoupling (electronics)

electronics Electronics is a scientific and engineering discipline that studies and applies the principles of physics to design, create, and operate devices that manipulate electrons and other Electric charge, electrically charged particles. It is a subfield ...

, decoupling is the prevention of undesired

electrical energy Electrical energy is the energy transferred as electric charges move between points with different electric potential, that is, as they move across a voltage, potential difference. As electric potential is lost or gained, work is done changing the ...

transfer ( coupling) between subsystems. A common example is connecting localized decoupling capacitors close to the power leads of

integrated circuit An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...

s to suppress coupling via the

power supply A power supply is an electrical device that supplies electric power to an electrical load. The main purpose of a power supply is to convert electric current from a source to the correct voltage, electric current, current, and frequency to power ...

connections. These act as a small localized energy reservoir that supply the circuit with current during transient, high current demand periods, preventing the voltage on the power supply rail from being pulled down by the momentary current load. Another common example of the use of decoupling capacitors is across the emitter

bias Bias is a disproportionate weight ''in favor of'' or ''against'' an idea or thing, usually in a way that is inaccurate, closed-minded, prejudicial, or unfair. Biases can be innate or learned. People may develop biases for or against an individ ...

resistor of transistor

common emitter In electronics, a common-emitter amplifier is one of three basic single-stage bipolar-junction-transistor (BJT) amplifier topologies, typically used as a voltage amplifier. It offers high current gain (typically 200), medium input resistanc ...

amplifiers to prevent the resistor absorbing a portion of the AC output power of the amplifier. Lossy

ferrite bead A ferrite beadalso called a ferrite block, ferrite core, ferrite ring, EMI filter, or ferrite chokeis a type of choke (electronics), choke that suppresses high-frequency electronic noise in electronic circuits. Ferrite beads employ high-frequen ...

s may also be used to isolate or 'island' sections of circuitry. These add a high series impedance (in contrast to the low parallel impedance added by decoupling capacitors) to the power supply rails, preventing high-frequency currents being drawn from elsewhere in the system. Electronic circuits {{electronics-stub