Zener diode connection method

Zener diode connection method

Selection of Current Limiting Resistors for Zener diode Circuits

If R is too large, Ir is very small. When Il increases, the current of the voltage regulator may decrease below the critical value, losing its stabilizing effect;

If R is too small, Ir will be large. When Rl is large or open, Ir will flow to the voltage regulator, which may exceed its allowable rating and cause damage.

When both cannot be met simultaneously, it indicates that the operating range of the voltage regulator has been exceeded under the given conditions. It is necessary to limit the range of changes in input voltage Ui or load current Il, or choose a larger capacity voltage regulator.

Izmax: The maximum allowable working current of the voltage regulator

Uzmax: Rectification output voltage at the highest grid voltage

Ilmax: maximum value of load current

simplified calculation

The current limiting resistor mainly considers the magnitude of the load current, rather than the minimum operating current of the voltage regulator,

(Input voltage stabilized voltage)/Maximum working current of the circuit=Current limiting resistor

Zener diode The minimum working current of the voltage regulator can generally be ignored.

There is another parameter that needs to be rechecked, which is the power of the voltage regulator at the minimum operating current of the circuit,

Shunt current on the voltage regulator&TImes; Voltage regulation value=the power of the voltage regulator, whether it is greater than the maximum power of the voltage regulator.