In electronics, gain is a measure of the ability of a circuit (often an amplifier) to increase the power or amplitude of a signal from the input to the output. It is usually defined as the mean ratio of the signal output of a system to the signal input of the same system. It may also be defined on a logarithmic scale, in terms of the decimal logarithm of the same ratio ("dB gain"). A gain greater than one (zero dB), that is, amplification, is the defining property of an active component or circuit, while a passive circuit will have a gain of less than one.

Thus, the term gain on its own is ambiguous. For example, "a gain of five" may imply that either the voltage, current or the power is increased by a factor of five, although most often this will mean a voltage gain of five for audio and general purpose amplifiers, especially operational amplifiers, but a power gain for radio frequency amplifiers, and for directional aerials will refer to a signal power change compared with a simple dipole. Furthermore, the term gain is also applied in systems such as sensors where the input and output have different units; in such cases the gain units must be specified, as in "5 microvolts per photon" for the responsivity of a photosensor. The "gain" of a bipolar transistor normally refers to forward current transfer ratio, either h_FE ("Beta", the static ratio of I_c divided by I_b at some operating point), or sometimes h_fe (the small-signal current gain, the slope of the graph of I_c against I_b at a point).

In laser physics, gain may refer to the increment of power along the beam propagation in a gain medium, and its dimension is m⁻¹ (inverse meter) or 1/meter.

Logarithmic units and decibels[link]

Power gain[link]

Power gain, in decibels (dB), is defined by the 10 log rule as follows:

Failed to parse (Missing texvc executable; please see math/README to configure.): \text{Gain}=10 \log \left( {\frac{P_{\mathrm{out}}}{P_{\mathrm{in}}}}\right)\ \mathrm{dB}

where P_in and P_out are the input and output powers respectively.

A similar calculation can be done using a natural logarithm instead of a decimal logarithm, and without the factor of 10, resulting in nepers instead of decibels:

Failed to parse (Missing texvc executable; please see math/README to configure.): \text{Gain} = \ln\left( {\frac{P_{\mathrm{out}}}{P_{\mathrm{in}}}}\right)\, \mathrm{Np}

Voltage gain[link]

When power gain is calculated using voltage instead of power, making the substitution (P=V ²/R), the formula is:

Failed to parse (Missing texvc executable; please see math/README to configure.): \text{Gain}=10 \log{\frac{(\frac{{V_\mathrm{out}}^2}{R_\mathrm{out}})}{(\frac{{V_\mathrm{in}}^2}{R_\mathrm{in}})}}\ \mathrm{dB}

In many cases, the input and output impedances are equal, so the above equation can be simplified to:

Failed to parse (Missing texvc executable; please see math/README to configure.): \text{Gain}=10 \log \left( {\frac{V_\mathrm{out}}{V_\mathrm{in}}} \right)^2\ \mathrm{dB}

and then the 20 log rule:

Failed to parse (Missing texvc executable; please see math/README to configure.): \text{Gain}=20 \log \left( {\frac{V_\mathrm{out}}{V_\mathrm{in}}} \right)\ \mathrm{dB}

This simplified formula is used to calculate a voltage gain in decibels, and is equivalent to a power gain only if the impedances at input and output are equal.

Current gain[link]

In the same way, when power gain is calculated using current instead of power, making the substitution (P = I ²R), the formula is:

Failed to parse (Missing texvc executable; please see math/README to configure.): \text{Gain}=10 \log { \left( \frac { {I_\mathrm{out}}^2 R_\mathrm{out}} { {I_\mathrm{in}}^2 R_\mathrm{in} } \right) } \ \mathrm{dB}

In many cases, the input and output impedances are equal, so the above equation can be simplified to:

Failed to parse (Missing texvc executable; please see math/README to configure.): \text{Gain}=10 \log \left( {\frac{I_\mathrm{out}}{I_\mathrm{in}}} \right)^2\ \mathrm{dB}

and then:

Failed to parse (Missing texvc executable; please see math/README to configure.): \text{Gain}=20 \log \left( {\frac{I_\mathrm{out}}{I_\mathrm{in}}} \right)\ \mathrm{dB}

This simplified formula is used to calculate a current gain in decibels, and is equivalent to the power gain only if the impedances at input and output are equal.

The "current gain" of a bipolar transistor, h_FE or h_fe, is normally given as a dimensionless number, the ratio of I_c to I_b (or slope of the I_c-versus-I_b graph, for h_fe).

In the cases above, gain will be a dimensionless quantity, as it is the ratio of like units (Decibels are not used as units, but rather as a method of indicating a logarithmic relationship). In the bipolar transistor example it is the ratio of the output current to the input current, both measured in Amperes. In the case of other devices, the gain will have a value in SI units. Such is the case with the operational transconductance amplifier, which has an open-loop gain (transconductance) in Siemens (mhos), because the gain is a ratio of the output current to the input voltage.

Example[link]

Q. An amplifier has an input impedance of 50 ohms and drives a load of 50 ohms. When its input (Failed to parse (Missing texvc executable; please see math/README to configure.): V_\mathrm{in} ) is 1 volt, its output (Failed to parse (Missing texvc executable; please see math/README to configure.): V_\mathrm{out} ) is 10 volts. What is its voltage and power gain?

A. Voltage gain is simply:

Failed to parse (Missing texvc executable; please see math/README to configure.): \frac{V_\mathrm{out}}{V_\mathrm{in}}=\frac{10}{1}=10\ \mathrm{V/V}.

The units V/V are optional, but make it clear that this figure is a voltage gain and not a power gain. Using the expression for power, P = V²/R, the power gain is:

Failed to parse (Missing texvc executable; please see math/README to configure.): \frac{V_\mathrm{out}^2/50}{V_\mathrm{in}^2/50} = \frac{V_\mathrm{out}^2}{V_\mathrm{in}^2}=\frac{10^2}{1^2}=100\ \mathrm{W/W}.

Again, the units W/W are optional. Power gain is more usually expressed in decibels, thus:

Failed to parse (Missing texvc executable; please see math/README to configure.): G_{dB}=10 \log G_{W/W}=10 \log 100=10 \times 2=20\ \mathrm{dB}.

A gain of factor 1 (equivalent to 0 dB) where both input and output are at the same voltage level and impedance is also known as unity gain.

See also[link]

• Active laser medium
• Antenna gain
• Aperture-to-medium coupling loss
• Automatic gain control
• Attenuation
• Complex gain
• DC offset
• Effective radiated power
• Gain before feedback
• Insertion gain
• Loop gain
• Open-loop gain
• Net gain
• Power gain
• Process gain
• Transmitter power output

 This article incorporates public domain material from the General Services Administration document "Federal Standard 1037C".

Jo Kwon
Background information
Birth name	Jo Kwon (조권)
Born	(1989-08-28) August 28, 1989 (age 22) Suwon, Gyeonggi Province, South Korea
Occupations	Singer, dancer, entertainer, actor, MC
Instruments	Vocal, piano
Years active	2008–present
Labels	JYP Entertainment
Associated acts	2AM 2PM

Jo Kwon (Hangul: 조권, born August 28, 1989) is a South Korean singer and entertainer, leader of ballad boyband 2AM.

Predebut[link]

Jo Kwon, commonly known as Sacre Bleu, is the longest-serving male trainee in JYP Entertainment, having trained for 2567 days; exactly 7 years and 12 days since joining JYP. He was chosen as the last members of Park Jin Young's "99% Challenge Project" along with Sunye of Wonder Girls.^{[citation needed]}

In 2008, he appeared on MNET's Hot blood, a program that showed the intense physical training that 13 male trainees had to go through for the opportunity to debut in either 4-member ballad group or 7-member dance group One Day under JYP Entertainment.^[1] After getting through the eliminations, Jo Kwon was given the position of 4-member ballad group's leader.He has been attending Kyung Hee University.^[2]

Debut[link]

2AM's first single "This Song" release July 21, 2008 and made their debut performance on July 11, 2008 performing "이 노래" ("This Song").^[3]

Solo Contributions[link]

Television[link]

Jo Kwon regularly appears as a regular guest on variety shows such as "Star King", popular for his playful and frivolous dance gags. He was part of "Dirty Eyed Girls" on an episode of 2PM's variety show "Wild Bunny", performing a parody of popular Brown Eyed Girls song Abracadabra. The music video became extremely popular.^[4] In September 2009, Jo Kwon was one of the main MCs for SBS's environmental variety show "Find it! Green Gold" with Super Junior member Shindong, SS501 member Kim Hyung Joon, and former Fly To The Sky member Brian Joo. He also replaced Jaebeom on historical culture variety show Nodaji after his internet controversy.^[5] Both shows were later canceled due to low ratings.^{[citation needed]}

He joined the cast of We Got Married on October 3, 2009, coupled up with Brown Eyed Girls member Ga-In. Although they were initially only supposed to feature for the Chuseok special, their appearance brought in the highest ratings yet for Season II, and they were announced a permanent couple.^[6] Jo Kwon was diagnosed with H1N1 on October 28, 2009, causing him to postpone filming We Got Married. The next day, a representative stated that Jo Kwon was recovering quickly after treatment.^{[citation needed]}

In 2010, he became a permanent cast member of Family Outing 2.^[7] He is also currently acting in the sitcom All My Love with co stars Park Min Sun, Kim Gab Soo and fellow idol and 'wife' Ga-In from Brown Eyed Girls.

Music[link]

He sang with Jinwoon in May Doni's "몰라-ing" ("Molla-ing"), as well as a duet with Changmin titled "졸업" ("Graduation") on February 5, 2009, and Baek Jiyoung's "밤새도록" ("All Night") on her 7th album Sensibility. He featured in Lee Seung Hwan's Special Album "Hwantastic" with the song "덩크슛" ("Dunk Shoot") a duet with Whale (from W&Whale)and also featured in the music video in September 2009.^[8]

He released a digital single "우리 사랑하게 됐어요" ("We Fell in Love") on December 16, 2009, a duet with his We Got Married partner Ga-in.,^[9] which topped variety online music charts, winning 2 awards on Music Bank's K-Charts and the "Most Popular Background Phone Music" on the Gaon Charts.^[10] 50 million won from the profits of the song were donated to help out for Haiti's earthquake.^[11] For these efforts, Jo Kwon was given an award at the 3rd Korea Sharing Awards ceremony.^[12]

Jo Kwon participated in Wax's repackaged album Unplugged Side A. He sang a duet with her titled "이별이야기" ("Farewell Song"), released on March 24, 2010.^[13]

On June 30, 2010, Jo Kwon released his first solo digital single titled "고백하던 날" ("The Day I Confessed"), a song he partially composed during the We Got Married broadcast for Ga-in. The song reached No. 1 on Cyworld real time charts the day after its release.^[14]

Jo Kwon appeared on an episode of 2 pm Show along with a member of 2 am Seul Ong

Filmography[link]

• 2010 – Running Man (guest ep 7) – SBS
• 2010–2011 All My Love [( Ok Yeob)] -MBC

Awards[link]

References[link]

External links[link]

• Jo Kwon's Microblogging on Cyworld
• Jo Kwon on Twitter
• Jo Kwon on Me2day

Michael Bay
on the set of Transformers (May 30, 2006)
Born	Michael Benjamin Bay (1965-02-17) February 17, 1965 (age 47) Los Angeles, California, U.S.
Occupation	Film director Film producer
Years active	1984–present

Michael Benjamin Bay (born February 17, 1965) is an American film director and producer. He is known for directing high-budget action films characterized by their fast edits, stylistic visuals and substantial practical special effects.^[1][2] His films, which include The Rock, Armageddon, Pearl Harbor and the Bad Boys and Transformers series, have grossed over three billion dollars world-wide.^[3] He is co-founder of commercial production house The Institute, a.k.a. The Institute for the Development of Enhanced Perceptual Awareness.^[4] He is co-chair and part-owner of the digital effects house Digital Domain.^[5] He co-owns Platinum Dunes, a production house which has remade horror movies including Friday the 13th, The Texas Chainsaw Massacre, and A Nightmare on Elm Street.^[6]

Early life[link]

Michael Bay was born and raised in Los Angeles, California. He was raised by his adoptive parents Harriet, a bookstore owner/child psychiatrist, and Jim, a CPA.^[7] Bay's grandfather was Russian.^[8] His cousin, Susan Bay, is the wife of Star Trek actor Leonard Nimoy.^[9] He attended the exclusive Crossroads School, in Santa Monica, California.^[10] Bay often traces his interest in action films back to an incident during his childhood. As a boy, he attached some firecrackers to a toy train and filmed the ensuing fiery disaster with his mother's 8mm camera. The fire department was called and he was grounded.^[11]

Career[link]

Bay got his start in the film industry interning with George Lucas when he was fifteen, filing the storyboards for Raiders of the Lost Ark, which he thought was going to be terrible. His opinion changed after seeing it in the theater and he was so impressed by the experience that he decided to become a film director.^[12] He graduated from Wesleyan University in 1986, majoring in both English and Film.^[13][14] He was a member of the Psi Upsilon fraternity and a favorite student of film historian Jeanine Basinger.^[15] For his graduate work, he attended Art Center College of Design in Pasadena where he also studied film.^{[citation needed]}

Michael Bay began working at Propaganda Films, directing commercials and music videos, two weeks after finishing his post-graduate degree.^{[citation needed]} His 90-second World War II-inspired Coca-Cola advertisement was picked up by Capitol Records. His first national commercial for the Red Cross won a Clio Award in 1992.^[16][17] He directed Goodby, Silverstein & Partners Got Milk? advertisement campaign for the California Milk Processors Board in 1993.^[18]

Bay's success in music videos gained the attention of producers Jerry Bruckheimer and Don Simpson, who selected him to direct his first feature-length film, Bad Boys. The film was shot in Miami in 1994 and starred Will Smith and Martin Lawrence. The action film proved to be a break-out role for Smith, who was segueing from television to films at that time. Shooting in Miami was a good experience for Bay who would later own a home in the city and spend a great deal of time there.^[19] The film was completed for $19 million dollars and grossed a remarkable $141 million at the box office in the summer of 1995.^[20] Bay's success led to a strong partnership and friendship with Jerry Bruckheimer.^[21]

His follow-up film, The Rock (1996), was an action movie set on Alcatraz Island, and in the San Francisco Bay area. It starred Sean Connery, Nicolas Cage and Ed Harris. It was also produced by Jerry Bruckheimer and Don Simpson, the latter of whom died five months before the film's release. The film is dedicated to him.^[22] Connery and Cage won 'Best On-Screen Duo' at the MTV Movie Awards in 1997 and the film was nominated for an Academy Award in the Best Achievement in Sound category for the work of Greg P. Russell, Kevin O'Connell, and Keith A. Wester.^[23][24]

In 1998, Bay collaborated with Jerry Bruckheimer again, this time as a co-producer, as well as directing the action-adventure film Armageddon.^[25][26] The film, about a group of tough oil drillers who are sent by NASA to deflect an asteroid away from a collision course with Earth, starred Bruce Willis, Billy Bob Thornton, Ben Affleck and Liv Tyler. It was nominated for 4 Oscars at the 71st Academy Awards including Best Sound, Best Visual Effects, Best Sound Editing, and Best Original Song.^[27] The film earned 9.6 million dollars on its opening day and a total of 36.5 million through the first weekend.^[28] The production budget, $140 million dollars, was one of the highest of the summer of 1998. Armageddon went on to gross over $553 million dollars worldwide.^[29]

In 2001, Bay directed Pearl Harbor. It starred Ben Affleck, Josh Hartnett, Kate Beckinsale and Cuba Gooding, Jr. The film was released on Memorial Day weekend in 2001. Again, Bay produced the film with Jerry Bruckheimer. The film received four Academy Award nominations, including Best Sound, Best Visual Effects, Best Sound Editing and Best Song. Again, Kevin O'Connell received another nomination for Best Sound, but he did not win. Pearl Harbor won in the category for Sound Editing.^[30] Michael Bay also directed the music video for nominated track "There You'll Be" by vocal artist Faith Hill.^{[citation needed]}

Bay reteamed with Will Smith and Martin Lawrence for Bad Boys II, an event which also marked Bay's fifth collaboration with Jerry Bruckheimer. The film grossed $138 million domestically, enough to cover the production budget, and $273 million worldwide, almost twice as much as the first movie.

In 2005, Bay directed The Island, a science-fiction film starring Ewan McGregor and Scarlett Johansson. It was the first film Michael Bay made without Jerry Bruckheimer. The Island cost $126 million to produce. It earned $46 million domestically and $172 million worldwide. Bay stated that he was not comfortable with the domestic marketing campaign as it confused the audience as to the true subject of the film.^[31]

In 2007, he directed and teamed up with Steven Spielberg to produce Transformers, a live action film based on the Transformers franchise. The film was released in the U.S. and Canada on July 3, 2007, with 8 p.m. preview screenings on July 2. The previews earned $8.8 million, and in its first day of general release it grossed $27.8 million, a record for Tuesday box office attendance.^{[citation needed]} It broke the record held by Spider-Man 2 for the biggest July 4 gross, making $29 million. On its opening weekend, Transformers grossed $70.5 million, amounting to a $155.4 million opening week, giving it the record for the biggest opening week for a non-sequel.^{[citation needed]} As of November 2007, the film has made over $319 million domestically and over $708 million worldwide.

Bay returned as director and executive producer for Transformers: Revenge of the Fallen, which was released on June 24, 2009 and went on to gross over $832 million worldwide. Although it received mostly negative reviews by critics,^[32] including aggressively critical reviews by American film critics such as Roger Ebert,^[33] Michael Phillips^[34] and David Denby (who referred to Bay as "stunningly, almost viciously, untalented"),^[35][35] the film was well-received by its intended audience and was one of the highest-grossing films of 2009.^[36][37] In 2010, it earned seven Golden Raspberry Award nominations and winning three: Worst Picture, Worst Director and Worst Screenplay.^[38]

As of 2009, Michael Bay's worldwide box office totals make him the director with the eighth highest domestic US gross of all time (not adjusted for inflation).^[39] It was also one of the best selling DVD and Blu-ray Discs of 2009, second only to Twilight in DVD format and the number one of all time in Blu-ray format until it was surpassed by Blu-ray sales of James Cameron's Avatar in April 2010.^[40][41][42]

Bay directed Transformers: Dark of the Moon, released on June 28, 2011.^[43] He may direct a sequel to the Bad Boys franchise or a "small" film he's been developing for years, tentatively called Pain & Gain.^[44] The true crime story, based on events described in a Miami Herald article^[45] written by Pete Collins, concerns a group of bumbling bodybuilders working together to commit a robbery.

Bay produced DreamWorks' I Am Number Four, based on a series of novels by authors James Frey and Jobie Hughes published by HarperCollins Children's Books. D. J. Caruso (Eagle Eye, Disturbia) directed.^[46][47]

Bay will co-produce One Way Out, a reality series that pits ordinary people against each other as they try to keep their pasts hidden and builds toward a showdown where all those secrets will be revealed.^[48]

Gideon's Sword, Douglas Preston and Lincoln Child's novel set for release in February 2011, was optioned by Bay Films and will be produced by Michael Bay. The main character, Gideon Crew, avenges the death of his father.^[49][50]

In June 2011, Bay confirmed that Pain & Gain was his next project and that it would have a budget of $20 million.^[51]

On February 13, 2012, Paramount Pictures announced that Bay will produce and direct a fourth Transformers movie with a scheduled release date of June 2014.^[52]

Production and FX companies[link]

Platinum Dunes[link]

Bay founded this production house with fellow producers Brad Fuller and Andrew Form in 2001.^[53] Platinum Dunes is named after one of Bay's first student films at Wesleyan University. Brad Fuller also graduated from Wesleyan and worked for Bay as an executive assistant before joining him in this business venture. The company's first film, a remake of the 1974 film The Texas Chain Saw Massacre, grossed $107 million dollars worldwide.^[54] Platinum Dunes produced lucrative remakes of classic horror films and introduced new directors like Sam Bayer and Marcus Nispel to feature film audiences. Their most recent horror film production, A Nightmare on Elm Street starring Jackie Earle Haley as Freddy Krueger, was released April 2010. The film made 32.9 million dollars in its opening weekend, covering nearly its entire 35 million dollar budget and went on to gross over 100 million dollars worldwide.^[55]

Paramount Pictures signed a first look deal with Platinum Dunes in 2009.^[56] As part of this new relationship, Paramount Pictures and Nickelodeon have brought the Platinum Dunes producers on to produce a new Teenage Mutant Ninja Turtles, rebooting the film series launched by New Line in 1990. Bay, Fuller and Form will co-produce with Galen Walker, Scott Mednick and Marina Norman.^[57]

Platinum Dunes is currently in the process of selling an unnamed TV series to a "major cable network" with Bay in talks to direct the pilot.^[58]

Digital Domain[link]

Bay and Wyndcrest Holdings, a Florida-based investment firm, acquired the digital effects company Digital Domain from James Cameron and Stan Winston in 1996, infusing the struggling business with a $50 million dollar investment.^[5] Digital Domain considered an initial public offering in 2009 but ultimately withdrew the offer, because of the lack of interest. Currently a work for hire visual effects production house, Digital Domain plans to expand its efforts in the video gaming industry and become a full-fledged motion picture production house. Headquartered in Venice, Los Angeles, California, the company is also working to open branches in Vancouver, Canada and the state of Florida.^[59]

The Institute[link]

After leaving Propaganda Films, Bay and producer Scott Gardenhour, also formerly at Propaganda, formed The Institute for the Development of Enhanced Perceptual Awareness^[60] (now known as The Institute), to produce commercials and other projects. Through The Institute, Bay has directed and produced spots for Victoria's Secret, Lexus, Budweiser, Reebok, Mercedes-Benz, and Nike. His most recent advertisement for Victoria Secret was the 2009 "A Thousand Fantasies" holiday campaign.^[61]

Awards and honors[link]

Bay has received five MTV Movie Awards: Best Movie and Best Summer Movie You Haven't Seen Yet for Transformers, Best Action Scene for Pearl Harbor, Best Action Scene for Bad Boys II, and Best Action Scene for The Rock.^{[citation needed]} In 1994, Bay was honored by the Directors Guild of America with an award for Outstanding Directorial Achievement in Commercials.^[62]

Michael Bay received the ShoWest 2009 Vanguard Award for excellence in filmmaking at the confab of theater owners.^[63]

Personal life[link]

Bay lives in Los Angeles and Miami with his two bullmastiffs, Bonecrusher and Grace, named for characters in Transformers and Armageddon, respectively. As a boy, he donated his Bar Mitzvah money to an animal shelter and often includes his bullmastiff dogs in his films.^[64] He had another dog, Mason. Mason the dog's last appearance in a film was as Miles' dog in Transformers. He died during production of that film in March 2007.^[65][66]

Filmography[link]

Feature films[link]

Television[link]

• Miami Vice (TV series) (1986) (actor - Goon #3)
• No Way Out (TV series) (announced) (producer)
• Cocaine Cowboys (TV series) (announced) (producer)

Music videos[link]

• "Soldier of Love" by Donny Osmond (1989) (director)
• "Angelia" by Richard Marx (1989) (director)
• "I'll Be Holding On" by Greg Allman (1989) (director) ... from the film Black Rain
• "I Love You" by Vanilla Ice (1991) (director)
• "I Touch Myself" by Divinyls (1991) (director)
• "Love Thing" by Tina Turner (1992) (director)
• "Do It to Me" by Lionel Ritchie (1992) (director)
• "You Won't See Me Cry" by Wilson Phillips (1992) (director)
• "I'd Do Anything for Love (But I Won't Do That)" by Meat Loaf (1993) (director)
• "Rock and Roll Dreams Come Through" by Meat Loaf (1994) (director)
• "Objects in the Rear View Mirror May Appear Closer Than They Are" by Meat Loaf (1994) (director)
• "Falling in Love (Is Hard on the Knees)" by Aerosmith (1997) (director)
• "There You'll Be" by Faith Hill (2001) (director) ... Theme from Pearl Harbor

References[link]

Notes

External links[link]

Wikimedia Commons has media related to: Michael Bay

• Official website
• The Institute
• Michael Bay at the Internet Movie Database
• Michael Bay at AllRovi