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Adjustable shunt regulator

TL431 Basic Circuit

Build a basic TL431 circuit with labeled pins, component values and connection guidance.

Package view

TL431 in a circuit

Physical SOT-23 package · separate feed, sense and load paths.

TL431CDBZR top-view SOT23 circuit: K1 fed by680ohm from12V,10kupperandlowerdivideratREF2,A3ground,1kloadand5.01Villustrativemeter.
No load capacitor is assumed. Check stability before adding one, and check the exact package pinout.

Connect it, step by step

Follow the component values and pin connections

Feed K through a resistor

A 680 Ω series resistor limits the current from 12 V.

Connect the divider

Equal 10 kΩ resistors place REF near half the output voltage.

Account for the load

The 1 kΩ load draws about 5 mA; the remaining cathode current is about 5 mA.

Component view