Crowbar may refer to:

Music

People

A crowbar circuit is an electrical circuit used to prevent an overvoltage condition of a power supply unit from damaging the circuits attached to the power supply. It operates by putting a short circuit or low resistance path across the voltage output (V_o), much as if one dropped a tool of the same name across the output terminals of the power supply. Crowbar circuits are frequently implemented using a thyristor, TRIAC, trisil or thyratron as the shorting device. Once triggered, they depend on the current-limiting circuitry of the power supply or, if that fails, the blowing of the line fuse or tripping the circuit breaker.

An example crowbar circuit is shown to the right. This particular circuit utilizes an LM431 adjustable zener regulator to control the gate of the TRIAC. The resistor divider of R₁ and R₂ provide the reference voltage for the LM431. The divider is set so that during normal operating conditions, the voltage across R₂ is slightly lower than V_REF of the LM431. Since this voltage is below the minimum reference voltage of the LM431, it remains off and very little current is conducted through the zener and cathode resistor. If the cathode resistor is sized accordingly, very little voltage will be dropped across it and the TRIAC gate terminal will be essentially at the same potential as MT1, keeping the TRIAC off. If the supply voltage increases, the voltage across R₂ will exceed V_REF and the zener will begin to regulate voltage, drawing more current through it. The voltage at the gate terminal will be pulled down to V_Z (the zener voltage), exceeding the gate trigger voltage of the TRIAC and latching it on.

Crowbar is an American sludge metal band from New Orleans, Louisiana, characterized by their extremely slow, low-keyed, heavy and brooding songs that also contain fast hardcore punk passages. Crowbar is considered to be one of the most influential metal bands to come out of the New Orleans metal scene. Their slow, heavy, and brooding style of metal is known to be influential in the sludge metal, doom metal, and stoner metal genres.

History

Origins (1988-1991)

The band dates back to 1988, when Kirk Windstein joined the premiere hardcore punk band Shell Shock in New Orleans. He met Jimmy Bower, who was their drummer, and both quickly became friends. The band collapsed when Mike Hatch, their guitarist, committed suicide in late 1988 (some Pantera fans believe that this was the inspiration for the song "Hollow" from their 1992 album Vulgar Display of Power). The band, replacing Hatch with Kevin Noonan, carried on as Aftershock, where Windstein and Bower began to play low-tuned hardcore punk mixed with doom metal. Under that name they released a demo in mid-1989, and then renamed themselves WREQIUEM, with Mike Savoie, their bassist, leaving the band (He went on to direct music videos for Crowbar, Down, and Pantera), and Todd Strange joined them. Then in 1990 they renamed themselves The Slugs, and released a demo in mid-1990, but the band collapsed. Kirk considered becoming the guitarist for Exhorder. But Kirk and Todd reformed the band, with Craig Nunenmacher as the drummer, who was later replaced by Tommy Buckley (Soilent Green), and Kevin Noonan again on guitar. The band renamed themselves Crowbar in mid-1991.