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).

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

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. 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.

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

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. 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. Both shows were later canceled due to low ratings.^{[citation needed]}

Fiona Bloom is a music industry publicist that runs the New York City agency The Bloom Effect, which represents numerous recording artists and organizes high profile events on behalf of the organization's music industry clientele.Billboard (Magazine) listed her among 140 music business Twiteratti to follow. The Bloom Effect organizes and publicizes launch parties, international music events, live shows, album publicity, digital marketing, artists and repertoire consulting, and promotion. The company has produced over 1000 shows, consulted on more than 200 album projects and has been a part of over 300 recording artists’ careers. The Bloom Effect's clients have included The Lyricist Lounge, Babygrande Records, Tommy Boy Entertainment, Spectre Music, Penalty Recordings, MIDEM, Stones Throw Recordings, Mixtape Riot, Game, Bloomsbury, Nelson George, Mudville (band), Maya Azucena, Bill Laswell, The Renaissance Hotel, Anthony David (singer), Roxy Cottontail, Sway DaSafo Saian Supa Crew and other notables. Avery Sunshine and Erin Barra are also among her clients. Bloom has also served as the publicist for UK rapper SWAY.

Dwayne Douglas Johnson (born May 2, 1972), also known by his ring name The Rock, is an American actor and professional wrestler who is signed to WWE, appearing on the Raw brand. He is often credited as Dwayne "The Rock" Johnson.

Johnson was a college football player. In 1991, he was part of the University of Miami's national championship team. He later played for the Calgary Stampeders in the Canadian Football League, and was cut two months into the 1995 season. This led to his decision to become a professional wrestler like his grandfather, Peter Maivia, and his father, Rocky Johnson. He gained mainstream fame as a wrestler in the World Wrestling Federation (WWF) from 1996 to 2004, and was the first third-generation superstar in the company's history. Johnson was quickly given a push as a heroic character in the WWF, originally billed as "Rocky Maivia", and then as "The Rock". He would subsequently turn into a villain as a member of the Nation of Domination in 1997. Two years after he joined the WWF, Johnson won the WWF Championship, and became one of the most popular wrestlers within the company's history for his engaging interviews and promos. Johnson is regarded by many as one of the greatest talkers in professional wrestling history, Rock was voted third by the fans for his microphone ability behind Roddy Piper and Stone Cold Steve Austin who were second and first respectively.

Mark Robert Michael Wahlberg (born June 5, 1971) is an American actor, film and television producer, and former rapper. He was known as Marky Mark in his earlier years, and became famous for his 1989 debut as frontman with the band Marky Mark and the Funky Bunch. He was named No. 1 on VH1's 40 Hottest Hotties of the 90's. Wahlberg is well known for his roles in films such as Boogie Nights (1997), Three Kings (1999), The Perfect Storm (2000), Planet of the Apes (2001), Rock Star (2001), The Italian Job (2003), I Heart Huckabees (2004), Four Brothers (2005), The Departed (2006), Invincible (2006), Shooter (2007), and The Fighter (2010), Date Night (2010). He has also served as the executive producer of the TV series Entourage, Boardwalk Empire and How to Make It in America.

Wahlberg was born in the Dorchester neighborhood of Boston, Massachusetts, the youngest of nine children, with siblings Arthur, Jim, Paul, Robert, Tracey, Michelle, Debbie (died in 2003 at age 44), and Donnie. His father was of half Swedish and half Irish ancestry, and his mother is of Irish, English, and French Canadian descent. Maternally, Wahlberg is distantly related to author Nathaniel Hawthorne. Wahlberg's mother, Alma Elaine (née Donnelly), was a bank clerk and nurse's aide, and Wahlberg's father, Donald Edward Wahlberg, was a Teamster who worked as a delivery driver. His parents divorced in 1982. Wahlberg had a Roman Catholic upbringing and attended Copley Square High School (but never graduated) on Newbury Street in Boston.