Allegretti & Witcoff, Ltd.
Voltage regulator with variable reference outputs for a hearing aid
 A voltage regulator for producing first and second reference voltages. The regulator includes first and second transistors, of a first polarity, having coupled emitters, and third and fourth transistors, of a second polarity, having coupled emitters. A first amplifier is driven by the collectors of the second and third transistors, and provides a signal to the bases of the third and fourth transistors. A fifth transistor, of the first polarity, has its collector interconnected to the base of the second transistor, and the emitter of which is interconnected to the emitter of the first and second transistors. A second amplifier is driven by the collectors of the first and fourth transistors, and provides a signal to the bases of the first and fifth transistors. The wiper arm of a variable resistance whose end terminals are connected between the base and collector of the fifth transistor provides an adjustable reference voltage output over the range of the first and second reference voltages. 
Beltone Electronics Corporation
H H H H H H H H H H H
H03G H03G H03H H03G H03G H04R H04R H03F H03F H03G H04R
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Richard James R.
Brander Anderson