Enter your Maximum and Minimum Input Voltage (Vin), Output Voltage (Vout), Load Current (Iload), and Zener Current limits (Iz Min / Iz Max) into this Zener Diode Calculator to find the Required Series Resistance, along with the Series Resistor Power Rating, Zener Power Dissipation, and Maximum Zener Current your circuit needs to stay stable.
Required Series Resistance
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Series Resistor Power Rating
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Zener Power Dissipation
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Maximum Zener Current
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A Zener diode is used in DC voltage regulator circuits to maintain a constant output voltage despite variations in input voltage or load current. It operates in reverse bias and has a specific breakdown voltage.
The series resistor limits the current through the Zener diode to prevent damage and ensures proper regulation. It drops the excess voltage between the input and the desired output voltage.
Exceeding the power rating can damage or destroy the Zener diode due to excessive heat generation. Always ensure the calculated power dissipation is below the diode's maximum rating with adequate safety margin.
The minimum Zener current (typically 1-10% of maximum rating) ensures the diode stays in the regulation region. Check the datasheet for the specific minimum current required for stable operation.
Vin Max is the highest input voltage the circuit will see, while Vin Min is the lowest. The circuit must regulate properly across this entire range, with the series resistor calculated for worst-case conditions.
Zener diodes typically provide regulation within 5-20% depending on the specific diode and operating conditions. For more precise regulation, consider using a voltage regulator IC instead.
Yes, you can connect Zener diodes in series to achieve higher voltages. The total voltage will be the sum of individual Zener voltages, but ensure current ratings are compatible.
Use at least 50-100% safety margin for power ratings. If the calculated power is 0.5W, choose a resistor rated for at least 1W to ensure reliable operation and longevity.