Electronics FAQ – Your Multilingual Guide to Electronics

  Why a Capacitor Is Called a Non-Dissipative Element – Capacitor Energy Storage, Lossless Element, Ideal Capacitor Explained A capacitor is called a   non-dissipative element   because it   stores electrical energy in its electric field without converting it into heat   during ideal operation. Unlike resistors, which   dissipate energy as heat , capacitors   absorb energy and return it to the circuit . In real life, small losses exist due to dielectric leakage and ESR, but ideally, a capacitor is considered   lossless . Dissipation means the generation of heat: In the above circuit, power is dissipated across R1 and R2. A capacitor does not generate heat:  In the same manner, we may think that power is dissipated across C and R, but in reality, power is dissipated across R only. Why? Because a capacitor simply charges and discharges through R. In short capacitor is just absorbing and releasing charge. No current flows through the capacitor b...

How Does a Capacitor Reduce Ripple in DC? Working Principle, Smoothing Effect, and Applications. Why is it important in AC to DC conversion?  Filtwer capacitor analogy with a water tank: Suppose your home has intermittent water supply problems. When you need water, the supply is not sufficient. When you don’t need water, you don’t know what to do about the excess water. What is the solution to this problem? Have a water storage tank, don’t you? Similarly, unfiltered, raw rectified DC voltage is not as smooth as battery voltage. Unfiltered DC voltage:  As shown above, sometimes it is zero, sometimes it is maximum. It is always varying with respect to time. But electronic devices require a smooth DC voltage, as shown below. DC voltage of Battery:  The solution is to incorporate an electronic reservoir called a capacitor . AC to DC conversion using a diode and a capacitor:  Filtered DC voltage ripple waveform: It stores excess electricity and releases it to the load whe...

Types of Capacitors – Ceramic, Electrolytic, Film, Tantalum, and Their Applications in filter, decoupling, coupling, bypass, reset and energy storage Explained. Filter  capacitor:   is generally a large value of an electrolytic capacitor used for filtering bumpy unidirectional current in a smooth DC voltage, like what we get from a battery. Decoupling capacitor:  It  is typically a ceramic or tantalum capacitor parallel with one end tied to the system DC ground. It decouples high-frequency noise by creating a low-impedance path to ground only for certain offending noise frequencies that would otherwise disturb the system's operation. Bypass capacitor ,  As shown in the figure below, it bypasses or shorts the AC component (of the input signal) to the ground without disturbing the DC biasing of the amplifier. This is done to increase the amplifier's gain by focusing the input signal on the base-to-emitter junction of the transistor, which would otherwise be wasted...

How Do Snubber Circuits Protect Relay Contacts? Working Principle, Benefits, and Design Tips. Explained the Snubber analogy with a shock absorber.  What is 'Snubber'? Snubber Circuit: A snubber circuit is a combination of a resistor and a capacitor. Why switch contact wears out that controls the inductive load? Relay contacts tend to wear out more if it is used to switch an inductive load. When the relay contact opens, the falling magnetic field generates a high voltage spike that results in a spark across the relay contact. A snubber is connected in parallel to the contact. The snubber absorbs the voltage spike. The resistor dissipates the energy stored in the capacitor when the contact closes. Analogy of Snubber:  A Snubber can be compared with the shock absorbers of a car. A spring acts like a capacitor that absorbs shock by compressing, and a damper acts like a resistor that dissipates energy stored in the spring into heat. Both in combination absorb shocks. FAQ Set: Q1: W...

How Does a Capacitor Work as a Voltage Regulator? Working Principle, Applications, and Circuit Examples of how capacitors stabilise the voltage level What is a voltage regulator? Voltage regulator’ is not a very appropriate word, although a capacitor does improve voltage regulation. A regulator is an (electronic) arrangement that maintains the output voltage within a predetermined narrow voltage tolerance band against input voltage fluctuations and load variations. ‘Stabilise the voltage level’ is what a capacitor does by bridging the gaps between the demand and supply of the load current. AC to DC conversion:  How capacitor regulate DC voltage? A capacitor charges to the peak of the incoming voltage level and tries to maintain it by supplying current to the load through self-discharge. FAQ Set: Q1: How can a capacitor regulate voltage? A capacitor regulates voltage by storing and releasing electrical energy, smoothing out fluctuations in DC voltage and providing a more stable outp...

How does a capacitor smoothens a voltage and how does an Inductor smoothen the current Take a large reservoir of water. Does the inlet of water increase the water level suddenly? No. Watertank analogy of a capacitor: Does the outlet of water suddenly decrease the water level? No. A capacitor is like a water tank. Inlet water is like a charging current. The outlet of water is like a discharge current. Water level is like the voltage of a capacitor. DC ripple filter: The process of how a capacitor maintains its voltage level is best explained by how a filter capacitor smoothens the DC ripple. When the incoming voltage increases, it charges to that voltage. When the incoming voltage decreases, it uses its stored energy to supply current to the load by maintaining the voltage level. As long as demand le less than supply, it comfortably maintains almost a constant level of voltage across the load. That is exactly what an overhead water tank in our home does when there is an irregular water ...

Disadvantages of Using a Large Value Capacitor as a Decoupling Capacitor – Effects, Limitations, and Circuit Considerations A decoupling capacitor is not a filter capacitor. It has a definite purpose of decoupling high-frequency noise, not the ripple of the power supply. Let's not confuse it with a bypass capacitor, parallel to the emitter resistance of the ‘common emitter amplifier’, which has a higher value necessary to preserve the low-frequency response of the amplifier. What exactly does a decoupling capacitor do? A decoupling capacitor has two distinct aims. Decouple noise frequency by providing a low impedance path to the ground. This noise could be because of other circuit operations of the same circuit or due to EMI/RFI noise pickup. To provide an instant current to stabilise the voltage. This is especially necessary for the digital switching circuits that put transient (short-duration) demand on the power supply. The decoupling capacitor must be of a low ESR type, such as...