TL431 is controllable precision voltage source Its output voltage with two resistance can be arbitrarily set to from Verf (2.5 V) to 36 V within the scope of any value.The device of the typical dynamic impedance is 0.2 Ω In many applications use it to replace the zener diode, for example, digital voltmeter, op-amp circuit, the adjustable voltage power supply, switching power supply, etc Programmable output voltage: 2.5 V ~ 36 V Three-terminal adjustable shunt reference source Specification: Voltage reference error: plus or minus 0.4%, typical values @ 25 (TL431B) Low dynamic output impedance: 0.22 Ω (typical) Load current 1.0 ma - 100 ma. Maximum input voltage of 37 v Maximum working current 150 ma Internal reference voltage of 2.495 V (25°C) Package Includes: 100 x TL431A TL431 Precision Shunt Regulators TO-92