Standard Zener Diode Voltages — Table & Part Numbers
Find the nearest standard Zener voltage and its BZX55 / 1N47xx part numbers, with the full 2.4–100 V reference table.
Standard Zener voltages, 2.4–100 V
The SMD BZX84C series (SOT-23) uses the same voltage coding as BZX55C — BZX84C5V1 is the surface-mount 5.1 V part. Check the datasheet for its power rating; it varies by manufacturer.
| Voltage | BZX55C… (500 mW) | 1N47xxA (1 W) |
|---|---|---|
| 2.4 V | BZX55C2V4 | — |
| 2.7 V | BZX55C2V7 | — |
| 3.0 V | BZX55C3V0 | — |
| 3.3 V | BZX55C3V3 | 1N4728A |
| 3.6 V | BZX55C3V6 | 1N4729A |
| 3.9 V | BZX55C3V9 | 1N4730A |
| 4.3 V | BZX55C4V3 | 1N4731A |
| 4.7 V | BZX55C4V7 | 1N4732A |
| 5.1 V | BZX55C5V1 | 1N4733A |
| 5.6 V | BZX55C5V6 | 1N4734A |
| 6.2 V | BZX55C6V2 | 1N4735A |
| 6.8 V | BZX55C6V8 | 1N4736A |
| 7.5 V | BZX55C7V5 | 1N4737A |
| 8.2 V | BZX55C8V2 | 1N4738A |
| 9.1 V | BZX55C9V1 | 1N4739A |
| 10 V | BZX55C10 | 1N4740A |
| 11 V | BZX55C11 | 1N4741A |
| 12 V | BZX55C12 | 1N4742A |
| 13 V | BZX55C13 | 1N4743A |
| 15 V | BZX55C15 | 1N4744A |
| 16 V | BZX55C16 | 1N4745A |
| 18 V | BZX55C18 | 1N4746A |
| 20 V | BZX55C20 | 1N4747A |
| 22 V | BZX55C22 | 1N4748A |
| 24 V | BZX55C24 | 1N4749A |
| 27 V | BZX55C27 | 1N4750A |
| 30 V | BZX55C30 | 1N4751A |
| 33 V | BZX55C33 | 1N4752A |
| 36 V | BZX55C36 | 1N4753A |
| 39 V | BZX55C39 | 1N4754A |
| 43 V | BZX55C43 | 1N4755A |
| 47 V | BZX55C47 | 1N4756A |
| 51 V | BZX55C51 | 1N4757A |
| 56 V | BZX55C56 | 1N4758A |
| 62 V | BZX55C62 | 1N4759A |
| 68 V | BZX55C68 | 1N4760A |
| 75 V | BZX55C75 | 1N4761A |
| 82 V | — | 1N4762A |
| 91 V | — | 1N4763A |
| 100 V | — | 1N4764A |
Reading Zener part numbers
Zener voltages follow the same E24 series as resistors. The BZX55C family writes the voltage into the part number with V as the decimal point — BZX55C5V1 is 5.1 V, BZX55C15 is 15 V. The 1N47xx family is simply sequential: 1N4728A is 3.3 V and each next number is the next E24 step, up to 1N4764A at 100 V.
Two practical notes. Around 5.6–6.2 V the temperature coefficient passes through zero (the zener and avalanche mechanisms cancel), so references are steadiest there. And below ~4 V the knee gets soft — regulation is noticeably worse, which is one reason 3.3 V rails are usually made with regulators rather than Zeners.
Related
Size the series resistor and check dissipation with theZener diode calculator, or see why these voltages look familiar in theE-series tables.
Common questions
- Which Zener series should I look in?
- For general-purpose work the 1N47xx series is the most widely stocked: 1N4728A is 3.3 V and the sequence runs in E24 steps up to 1N4764A at 100 V. The BZX55C and BZX79C families cover similar ground in smaller packages. If a design calls for a value not in the table, the usual answer is to pick the nearest standard part rather than hunt for an exact one.
- Why is the part number written 5V1 instead of 5.1V?
- It is a European convention where the unit letter replaces the decimal point, so 5V1 means 5.1 V, 3V3 means 3.3 V and 12V means exactly 12 V. It exists because a printed or photocopied decimal point is easy to lose, whereas a letter is not. You will see the same trick in resistor markings, where 4R7 means 4.7 Ω.
- Does a Zener actually regulate at exactly its rated voltage?
- No — the rating is a nominal figure measured at a specified test current, and the actual voltage moves with current and temperature. Tolerance suffixes tell you how much: an "A" part is typically ±5%, "B" ±2%, "C" ±5% depending on family. Below about 5 V the coefficient is negative and above about 6 V it is positive, which is why 5.6 V parts are prized for reference work — that is roughly where the two effects cancel.
- Can I put Zeners in series to get a voltage I need?
- Yes, and it is a standard trick — the voltages simply add, so a 5.1 V and a 6.2 V in series give 11.3 V. They must carry the same current, which they will if wired in series. What you cannot usefully do is put them in parallel: the lowest-voltage part conducts first and the others never reach their knee, so the pair behaves as one Zener with all the current in it.