BJTs Bipolar Junction Transistors

Theory

Applications

Voltage Reference - VBE Multiplier

Rubber Diode VBE multiplier.

For a simple reference voltage, a VBE multiplier (or rubber diode) can be implemented to regulate the output voltage to a consistent level for voltage reference. A Zener regulator or negative linear regulator could also be implemented. However, I found this circuit to be a good middle ground between linear performance and operating configurability. The rubber diode exploits a BJT’s VBE drop and voltage divider properties to set a voltage reference for small loads. This circuit is nice because it is both simple like a Zener regulator but configurable in its voltage output, similar to a linear regulator IC.

References

1

A. S. Sedra, K. C. Smith, T. C. Carusone, and V. Gaudet, “Chapter 6: Bipolar Junction Transistors (BJTs),” in Microelectronic circuits, New York, NY: Oxford University Press, 2021, pp. 60–73.

2

P. Horowitz and W. Hill, “Chapter 2: Bipolar Transistors,” in The Art of Electronics, New York: Cambridge University Press, 2022.