Voltage-regulator tube
（重定向自VR tube）
![Schematic representation of a cold cathode voltage-regulator tube](/Images/godic/202502/20/Ccvrt.svg1235.png")
![5651 Regulator tube in operation](/Images/godic/202502/20/5651RegulatorTubeInOperation1235.jpg")
A voltage-regulator tube (VR tube) is an electronic component used as a shunt regulator to hold a voltage constant at a pre-determined level.
Physically, these devices resemble vacuum tubes, but there are two main differences:
Electrically, these devices resemble Zener diodes, with the following major differences: