CURRENT: It is the flow of electrons inside elements, such as wires and electronic components. It is the rate of electron flow per unit time (second.) If cars were electrons then current will be the number of cars (passing some road) in one second, may be 10 cars per second! Unit is in Ampere (A).

VOLTAGE: It is what causes electrons to move from one point to another, it is also called potential. The potential between two points (of some electronic device) will cause certain number of electrons to flow between these two points. Voltage is analogical to the water pump pumping water inside water pipes. The higher the potential (pump strength) the higher the current (electrons per second) flowing between these two points. Voltage is what puts current into motion. Unit is in Volt (V).

RESISTOR: This component basically resists the movement of electrons inside them. Electrons flow inside wires the same way water flows inside the water pipes. Resistors are placed in certain positions of the circuit to reduce the electron flow in that path the same way water pipes reduce water flow when pipes become smaller in diameter. High resistor value (narrower water pipes) cause less electrons (water) to flow in them. Resistors are also used to deliver electrons to certain positions in the circuit and distribute different voltage values (potentials) at different locations. When electrons flow inside resistors they loss momentum (energy) in form of heat, so if the electrons enter one side of resistor they leave the second resistor side with lower energy than they had when they entered the first side. Some resistors will actually produce heat that can be used to cook your food. Resistor unit is in Ohm or Omega (W ).

CAPACITOR: This component stores electrons (not current) inside it when electrons flow toward it. When electrons have the chance to escape the capacitor they will but it takes some time to completely evacuate the capacitor, depending on how they have been evacuated from the capacitor. Because it takes time for electrons to discharge from the capacitor sometimes capacitors are used as timing device. Other electronic devices help imprisoned (stored) electrons escape from capacitor when connected to the capacitor. Their escape rate (discharge rate) greatly depends on how easy to escape via connecting other electronic devices to the capacitor (is there high or low resistance?.) If resistance is low the escape rate (discharge) is high (fast timer), if the resistance is high the escape rate will be low (slow timer). This is identical to the sand clock where if the sand clock middle junction trunk is narrow then more time is required to empty one side into the other. High resistance is identical to narrower trunk and Low resistance is identical to wider trunk. Capacitor Unit is in Farad (F).

INDUCTOR: This component is similar to the large wheel of fortune. Once the electric current (electrons per second) starts flowing in them (heavy wheel starts to rotate) the inductor will tend to keep the current flowing (heavy wheel got inertia and keeps rotating) and resist to suddenly stop current flow (since wheel is heavy it will not stop easy and suddenly). If you attempt to suddenly stop the current in the inductor (heavy wheel is now moving) something wrong may occur, such as generation of reversed high voltage across it. This induced reversed high voltage may be damaging or lethal if not generated intentionally. This phenomenon is used to generate thousands of volts inside your TV set from power of your house electrical outlet (110 or 220 VAC). Therefore the current in the inductor (moving wheel) must be slowed down until brought to zero motion and not suddenly stopped. This phenomenon is also used inside of your car engine since it can generate high voltage to produce electrical spark and ignite the gas inside the engine. Unit is in Henry (H).

DIODE: Stands for DI (Two) ODE (odd) or two of the odds - two of the ones. This device is made of two opposite semiconductor elements, the POSITIVE ANODE (P) and NEGATIVE CATHOD (N) or the PN junction. Electric conventional current flows inside the diode from Anode to Cathode but not the other direction. For that diode are used for power rectification to cause AC to be rectified to DC. Zener diodes are special case and are used to flow in them reverse current from Cathod to Anode when Zener voltage (or higher) is applied backward across them. This has many useful applications such as voltage regulation. Diodes in general are used as switches, they turn electrical current ON and OFF. They are also used to mix Radio signals, amplify small signals, and other signal conditioning circuits. The diode has no unit.

TRANSISTOR: This device is similar to the diode but with third junction added (for Bipolar Junction Transistors - BJT). Transistors have two main functions, 1. to switch electric current ON or OFF or 2. to amplify electronic signals. Signals could be audio, video, data, or other. Transistors are mainly specified by polarity (NPN or PNP), max power handling, frequency handling capability (or Gain Bandwidth Product - GBP), package type, Beta gain factor (for BJT transistor), switching speed, and other... No unit is available for transistors.

LED: Light Emitting Diode is a diode that emits light when electric current is applied in the forward direction, from Anode (+ pin) to Cathode (- pin). LED may be used to give an indication of some signal. If power is applied in the reverse direction the LED stays OFF, hence current doesn't flow from cathode to anode (reverse direction.) No unit available for the diode LED.

IC CHIP: Integrated Chip or IC. It is a collection of transistors, resistors, diodes, and other devices put inside one single IC package to perform in certain manner. An example would be memory IC, Microcontroller, and other hi tec single chip custom made IC circuits. One single IC may contain millions of transistors and resistors and are used inside your computer (such as the Central Processing Unit - or CPU.) No unit is associated to IC.

MICROCONTROLLER: Is the IC chip that acts as a little embedded computer inside any device such as home appliances (TV, Radio, Microwave oven…) or inside you car cruise control system. Microcontroller Unit (MCU) or its cousin (Digital Signal Processor - DSP) have a built in intelligence (software program) used for manipulating various inputs and outputs to lead us to certain desirable results. They can do things that we human can't do and are sometimes millions of times faster than us, but they will never be better than human though!, this depends on how you define "better". Hopefully they will make our life easier and more enjoyable! No units are available for MCU or DSP.

TRANSFORMER: It is a device that is used to transform voltage and current to lower or higher values while theoretically maintaining constant power, meaning there is no loss of power between input and output. Power equals Voltage times Current. Since power across input and output remains constant during transformation the product of both Voltage and Current should theoretically remain same. This can be envisioned as a signal source (audio, video, or other) connected to one side of transformer (input or primary), the other side (output or secondary) will either provide equal, higher, or lower voltage depending on the type of the transformer. Transformer is specified by its PRIMARY and SECONDARY turns ratio and power handling capability. Applications include voltage conversion, power transmission lines, impedance matching, RF and microwave applications, audio and Video, and more... No unit is available for Transformer.

PASSIVE: Any device that produces heat when electric current goes through it, such as resistor.

REACTIVE: Is a device that stores energy or electrons inside it and supplies it back on demand, such as capacitor and inductor. In the capacitor the current always move inside before the voltage forms on its pins (voltage lagging). In the inductor the voltage forms across its pins before the current moves inside it (voltage leading).

ACTIVE: Any device that provides energy or electrons, such as the battery.

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