Electronics & Software – Tips & Guide


Why do capacitors and inductors store energy but resistors do not?

Why do capacitors and inductors store energy but resistors do not?

In capacitors we have the ability to store charge and have potential differences due to the field between them. A magnetic field with which energy can be stored can also act in inductors.

Where, as if we encounter resistance, we can only have a power loss because it is opposite to the current. You may also find that AC capacitors and inductors offer imaginary resistance, i.e.  an impedance that does not generate power loss, but refers to stored energy. That is why we always take the actual resistance into account when calculating the power loss, but not the impedance.

A capacitor stores electrons as a static charge, an inductor as a magnetic field. A resistor is a simple passive device.

If you think of electricity as water, a capacitor is like a rubber membrane over a pipe, an inductor is like an axial turbine (water turns, it keeps turning and pumps water for a while after the flow stops), the resistance is accurate like a pipe, the dimensions of which determine the water flow.

For the capacitor (C) – Whenever a voltage is applied to its terminals, it receives charges in one direction (ENERGY STORAGE) and maintains this charge until the discharge path is created.

This principle used, each time we use C as a decoupling objective, this energy is supplied to the devices.

For inductance (L) – When a constant DC voltage is applied, NO ENERGY is stored there. L only shows its magic when- CHANGING VOLTAGE (AC) is applied.

This changing voltage produces a magnetic flux, and when the direction of the current tends to change, this flux collapses and produces BACK EMF, nothing energy stored in the inductor.