This one can throw people off a bit; many confuse Inductance and Capacitance, which are pretty similar on this question.

A capacitor is a passive component that consists of at least one pair of conductors separated by a dielectric (an insulator). When voltage is applied to the capacitor (creating a difference in potential between the two) it creates an electric field across the dielectric which stores energy. The easiest way for me to remember these is that an inductor, being a coil of wire, is used to create an electromagnet (you can make an electromagnet by wrapping a coil of insulated wire around a nail, for example), and so an inductor stores energy in a magnetic field. The capacitor stores energy in an electric field.

Once again:

What is the ability to store energy in a MAGNETIC field called? Inductance

What is the ability to store energy in an ELECTRIC field called? Capacitance

MICE acronym for above = Magnetic & Inductance pair while Capacitance & Electric pair

Last edited by kd7bbc. Register to edit

Tags: electronics definitions capacitance

The basic unit of capacitance, the Farad, is named for the physicist Michael Faraday.

The other units listed here are:

• the Volt - basic unit of voltage
• the Ohm - basic unit of resistance
• the Henry - basic unit of inductance

"Henry was Inducted into the hall of fame, and Faraday tipped his Cap(acitance)."

An additional memory aid: Many of us have heard of a Faraday Cage. Cages CAPture things (CAPacitance)

Last edited by kd7bbc. Register to edit

Tags: electronics definitions capacitance

An inductor is a coil of wire, usually around a non-ferrite (nonmagnetic)
core. The basic unit of inductance is the henry. Whenever you make a coil of wire, it creates a magnetic field; think of an electromagnet, which is basically an inductor with a ferrite core. The ability to store energy in such a field is Inductance. So remember -- _inductance creates a magnetic field

Capacitance has a very similar (and in fact opposite) effect to an inductor and creates an electric field.

Last edited by thewitcherhome. Register to edit

Tags: electronics definitions inductance

An inductor is a passive electrical component that stores energy in a magnetic field; its unit is the henry, which is named for Joseph Henry.

It's good to know what the other units listed are as well, since they are all real units:

• the coulomb - unit of electric charge
• the farad - unit of capacitance
• the ohm - unit of resistance

Study Tip: Consider using the line "Henry was inducted into the hall of fame, and (Farad)ay tipped his Cap(acitance)" to jog your memory.

Last edited by kd7bbc. Register to edit

Tags: electronics definitions inductance

Hertz is the standard unit for frequency, as used in the SI unit system. It is defined as the number of cycles per second of something periodic. For example a quartz clock ticks at \(1\)Hz. The wall outlet AC (in the US) is set to \(60\)Hz. The tone of A just below middle C is \(220\) Hz. The unit is named after Heinrich Hertz](wiki/Heinrich_Hertz). Here is a graphical example from Wikipedia.

The other (incorrect) answers here are:

• the farad - unit of capacitance
• the henry - unit of inductance
• the tesla - unit of magnetic field strength. \(31 µT\) (\(3.1 \times 10 − 5 T\)) - strength of Earth's magnetic field at 0° latitude (on the equator)

Last edited by crd716. Register to edit

Tags: frequencies definitions

RF is short for "Radio Frequency". The other listed options mean:

• AF - no meaning particular to ham radio, but could be AirForce
• HF - High frequency, commonly refers to frequencies between 3 and 30Mhz
• VHF - Very High Frequency, commonly refers to frequencies between 30Mhz and 300Mhz

Last edited by bud 357. Register to edit

Tags: radio waves definitions

Electromagnetic waves are radio waves. Radio waves are typically denoted by electromagnetic wavelengths longer then Infrared. As with all electromagnetic waves, they travel at the speed of light.

The other wrong options:

• Gravity waves - wave that have the restoring force of gravity or buoyancy.
• Sound waves - a sound wave is a type of pressure wave.
• Pressure waves - propogate via particle collisions and is formed from alternating compressions and rarefactions.

Last edited by bud 357. Register to edit

Tags: radio waves definitions

\[P={E}\times{I}\]

\[E=\frac{P}{I}\]

\[I=\frac{P}{E}\]

• P for Power (Watts)
• E for Electromotive Force (Voltage, Volts)
• I for Intensity (Current) (Amperes, Amps)

An easy way to remember is "Pixie". P I x E

Last edited by galaxy01. Register to edit

Tags: formulas math electrical power electrical current electromotive force (voltage) power law

\(P = I \times E\) \(=\) \(10 \times 13.8\) \(=\) \(138\) watts

The formula for electrical power is \(P = I \times E\).

"Power (in watts) equals Current (in amperes) multiplied by Potential Energy (in volts)."

\(P\) (watts) = \(10\) (amps)\(\times 13.8\) (volts)

\(10 \times 13.8 = 138\)

\(138\) watts

Last edited by kd7bbc. Register to edit

Tags: math dc power electrical power electromotive force (voltage) electrical current power law

Power is the rate of of electrical energy generation or consumption.

\(P = V \times I\) (watts \(=\) volts \(\times\) amperes)

Where \(P\) is power (\(W\)), \(V\) is voltage (\(V\)), and \(I\) is current (\(A\)).

• \(P = I \times V\)
• \(V = 12V\)
• \(I = 2.5A\)

\(P = 12V \times 2.5A = 30W\)

Last edited by kd7bbc. Register to edit

Tags: math dc power electrical power electromotive force (voltage) electrical current power law

We will use the Power Law, which is most commonly written as:

\[P = I \times E\]

We are given:

\begin{align*} \text{(Power) } P &= 120\text{ watts}\\ \text{(Current) } I &= \text{?}\\ \text{(Voltage) } E &= 12\text{ volts}\\ \end{align*}

To solve for \(I\) we can divide both sides by \(E\) and get

\begin{align*} I &= \frac{P}{E}\\ I &= \frac{120}{12}\\ &= 10\text{ amperes} \end{align*}

Last edited by victorlerp. Register to edit

Tags: math ohm's law electrical current electrical power