A precision regulator that employs the IC thusly is shown in this circuit. An operational amplifier compares the output voltage with the output voltage of a reference zener. The op amp controls the LM108 by driving the ground terminal through an FET. The load and line regulation of this circuit is better than 0.001%. Noise, drift and long term stability are determined by the reference zener, D1. Noise can be reduced by inserting 100 k, 1% resistors in series with both inputs of the op amp and bypassing the non-inverting input to ground. A 100 pF capacitor should also be included between the output and the inverting input to prevent frequency instability. Temperature drift can be reduced by adjusting R4, which determines the zener current, for minimum drift. Here is a schematic drawing:
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