What is the difference between power electronics and electronics?

I use maintly with my trainees this expression 

The difference between Electronics and Power Electronics is that of between a sea and an ocean !

What really makes the difference is the scale of the  physical parameters dealing with in each field specifically the Ampere and the Voltage 

This question can be answered in number of ways.
The simplest way to say all the electronics devices which deals with power are covered in Power Electronics.
There are devices which you do use in general purpose electronics like: Diode, BJT, MFETs etc.
You will find these devices in electronics & power electronics both.
The devices used in Power electronics may differ in term of construction & behavior from those used in electronics.
There are type of devices which you will find only IN PE, ex: IGBT anther answer ordinary devices are low current and low voltage devices.
power devices are high current and/or high vlotage devices.
ordinary devices generally can be for very high frequency.
power devices , again generally, for low to medium frequency.
the frequency classification is just for understanding though exceptions are there

Power Electronics is the branch of electronics which uses electronic circuits in controlling the flow of electrical energy.
Basically Power Electronics is a hybrid field which merges the field of electrical power systems and solid state electronic devices  such as Thyristors, IGBT, SCRs utilizing their ability to act as very fast switches.
The main application of Power Electronic circuits are in energy converters.
What is the difference between power electronics and electronics or more properly linear electronics? To highlight the difference we will mention the specifications by which they are respectively characterized; Linear Electronics: Gain and Bandwidth Power Electronics:  Efficiency and Distortion In power eelectronics the keyword is control as in motor drives, lighting circuits, SMPS and so on.
applications are mostly in high voltage high power switching circuits.
In linear electronics, the keyword is both control and amplification.
applications ate mainly in low voltage and low power circuits 

Power Electronics is related to Higher Voltages 220 or above.

Electronics is related to lower voltages devices operations upto 30 volts.

 

They are all electronics but power is one part of electronic, which foucuses on voltage and current of the signals. also power managment process e.g. AC to DC conversion and DC to DC managment e.g. stepping up and stepping down voltages. 

Power electronics refers to device used in switch mode: Electrical osses in the best case appear only during the switching from on-state (low Voltage - High current) to the off-state (High voltage - no current). In general this is achieved at relatively low frequency. In Analog electronics the device are used in general following sinus(t) signal. Various classes of operation are used (e.g. A, AB, B, C) which are associated with dissipated powers. In analog electronics one try to use also devices in switch mode (class D, E, F, S) but this is difficult to be achieved as the frequencies rise. Analog and power electronics are 2 different worlds, but there are bridges between them.

Power Electronics is a Branch of Electrical. But the Electronics components used for High power Conversions and Inversions of Electrical Power, Some of Power Electronic Components are SMPS,ONLINE UPS,OFFLINE UPS,3 PHASE PWM INVERTERS,VFD,AVR,..

je crois que c'est une branche ou un module intégré avec le monde vaste de l'électronique, mais elle est utilisée, généralement, dans l'étude d'alimentation des différents cercuit électronique.

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Power Electronics is the sub branch of electronics.Power electronics deals all the power controlled devices and power control techniques. You can find many applications of power electronics around you like Motor drives, Chargers, UPS systems, Power Supplies etc.

Electronics in general is a study that deal with the behavioral flow of electrons in a certain medium. But if we classify electronics to power electronics, electronics deal with low power devices such as ordinary resistors, capacitors,op amps, etc. While in power electronics, we will be dealing with high power devices and also with magnetism. Because magnetism occurs and very evident when there is a high power that leads to a high current flow within the medium. Thus the electric field and the magnetic field is being studied rigorously.

Electronics is no more a single subject of study anymore , nowadays there are multiple branches of electronics and they have their own Major Faculties. The basic branches are -Telecommunications / AV Consumer Electronics / Power Electronics / Computer Applications & Digital Electronics / Security & Survelance Electronics / Automotive Electronics etc. to name a few.

Power Electronics is the branch of electronics which deals in Electrical Power supply / Energy  related applications both in the Industrial and Home domains , this field covers Power Solutions / Generation / applications / Appliances and Devices / Transmission / Consumption & Conversion etc. covering any source where electrical energy is required. This is a mojor branch in Electronics Engineering.

The Term Electronics is a general nomenclature for study of Semiconductors and their applications. Electronics Engineering cannot be clubbed into one subject today.