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The main power supply for the RaceGauge system is a laptop computer
supply purchased from Jameco (part number
109276) for about $8. A technical document describing this power supply
is avaiable here. This
supply has +5v, +12v, -26v, and 350Vac outputs. Unfortunately the high-voltage output did not have enough power to light both of the LCD backlights, so another supply was used. This supply is a very compact high-voltage converter purchased for $20, also from Jameco. It converts 12 volts into about 750 volts, and produces enough current to power both LCD backlights. The +12v output from the main supply powers the high-voltage inverter, while the -26v output is used (along with a potientiometer for contrast adjustment) for the LCD drive voltage. The +5v output from the main supply powers all of the logic, including the MPU board and LCD modules. This main power supply is clever enough to have a built-in electronic switch, which can be used to activate or de-activate all of the power supply outputs. |
