Power Supply Efficiency
Boost
Increase your power supply efficiency by using a QBAR®
switch to lower the parasitic current drain through the
bleeder resistor during normal supply operation. A QBAR®
switch, OFF during normal operation, is turned ON at
supply turn-off and stays ON when all voltages fall to
zero. |

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Indicate Status Simply and Reliably
HI on the status line
drives GO indicator through a power MOSFET or Darlington.
LO on a status line drives the NO GO indicator through
the QBAR® switch; a
break or a short to ground in status line will also drive
the NO GO indicator. Requires only the indicator/display
supply - no local logic supply. |

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QBAR® Switch in Parallel with
Fragile or Trigger Device
A QBAR® switch protects the load from being driven by
false signals when all status indicators are not OK.
Damage to fragile loads such as laser diodes, or
erroneous firing of detonators can be avoided with a QBAR® switch. It shunts drive current I around
the load when any Status Gate input is lost, or when the
conductor from the Status Gate output to the QBAR® switch input is cut or shorted to ground. Also
when power supplies are ramping up or down. |

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Protects
Fragile Inputs on Cold Boards from Insertion into Hot
Systems
Boards, PCMCIA
peripherals, or subassemblies containing components which
can easily be damaged electrically are often overstressed
when accidentally inserted into a hot system. Such damage
(which may not show up until later) can be prevented by
shunting damaging currents around sensitive inputs with a
normally-closed QBAR®
switch. |

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