3. The TI LM4040 2.5-V voltage-reference curve shows its high voltage accuracy even when biased well below 100 µA. Using the same 12-V example as above, but with 75 µA for I z instead of 5 mA ...

Likely the sensor is one or several small signal diodes. Want to drastically improve reception of an old receiver? Try swapping out the 1N34 detector diode (1VFD) for a 1N60p (0.25 VFD).

Much better to use signal diodes or schottky signal diodes to steer them into a pre-biased zener or voltage rail. Avoid anything that are designed for power supply – zener diodes, rectifying ...

Connect a signal diode in series with a 1N756 8.2V zener so that the diode's negative-temperature coefficient cancels part of the zener's positive-temperature coefficient ().The diode's temperature ...