Voltage regulator circuit of regulated tube

First, the circuit composition

The regulator circuit composed of Zener diode dz and current limiting resistor R is the simplest DC regulated power supply. Two basic relations can be obtained from the regulator circuit of the regulator tube :

Ui=ur+uo

Ir=idz+il

Voltage Regulator Tube volt-ampere characteristics such as, in the voltage regulator circuit, as long as the regulator is always working in the voltage regulator zone, that is, to ensure the current of the regulator tube:iz<idz<izm, the output voltage UO is basically stable.

Second, the principle of voltage regulation

For any voltage regulator circuit should be examined from two aspects of its voltage regulation characteristics:

1. Power grid voltage Fluctuation

2. Load Change

1. Power grid voltage Fluctuation

When the power grid voltage rise, the voltage regulator circuit of the input of the UI increases, the output voltage UO also proportional increase, due to uo=uz, according to the Volt-ampere characteristics of the regulator tube, the increase of Uz will make the idz increase sharply, the IR will inevitably increase with the IdZ, ur at the same time with the IR and sharply increased, The increase of ur will reduce the output voltage UO. Therefore, as long as the parameter selection is appropriate, the voltage increment on R can be approximately equal to the increment of the UI, thus making the uo basically unchanged. A brief description is as follows:

When the grid voltage drops, the change in power varies with the above process.

It can be seen that when the voltage of the grid changes, the voltage regulator circuit offsets the change of the UI by changing the current of the current limiting resistor R, i.e. Δur≈δui, so that the UO is not changed.

2. Load Change

When the load resistance RL reduces the load current IL increases, the IR increases, UR also increases, UO must decline, that is, the UZ decline, according to the Volt-ampere characteristics of the regulator tube, the uz decline so that the idz sharply reduced, so that the IR with a sharp reduction of IR with it. If the parameter is properly selected, the Δidz≈-δil can be made so that the IR is basically unchanged, thus the UO is basically unchanged. A brief description is as follows:

Obviously, in the circuit as long as the Δiz≈-δil, you can make the IR basically unchanged, so as to ensure that the uo basically unchanged.

To sum up, in the voltage regulator diode composed of the voltage regulator circuit, the use of voltage regulators to adjust the role of the current, through the voltage limiting resistor r or the change of current to compensate to achieve the purpose of regulation. Current limiting resistor r not only limits the voltage in the regulator tube, but also works with the regulator to achieve the purpose of voltage regulation.

Voltage regulator circuit of regulated tube