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Revision as of 20:06, 24 May 2004 by 213.51.209.230 (talk)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)A voltage regulator is a mechanical, solid state or vacuum tube device designed to regulate DC voltage levels.
Early automobile generators and alternators had a mechanical voltage regulator using three or two relays and ballast resistors to stabilize the generator's output on 6 or 12 V, independent of the engine's Rpm. Later designs used 'solid state' technology to do the same.
In other devices one would use a transformer to bring the mains AC power down to a lower AC voltage, then use a rectifier (diode bridge) to convert AC to DC, followed by a voltage regulator or Zener diode to stabilize it to whatever design voltage.
Solid state regulator semiconductor chips come in either fixed or variable styles. A common solid state voltage regulator series is the LMxxxx and common fixed voltages are 5 V (for Transistor-transistor logic circuits) and 12 V, e.g. in personal computers.
In fixed voltage regulators the third pin is tied to ground, whereas in variable regulators the third pin goes through a potentiometer and then to ground. The potentiometer allows variable adjustment of the regulated voltage by the user.
See also: Switched-mode power supply