# Numbering of Diodes and Transistors

I'm an electronic enthusiast, and very interested in doing experiments and working with whatever I learn in the book.

Recently, I was making a full wave rectifier circuit. In order to find a Zener diode for this purpose, I searched through the net, and it was a utter chaos that I found myself in with the different types of numbering of the diodes and capacitors. My book mentioned that Zeners are numbered usually as 1N.... , that is, Zeners have the prefix 1N. I had to look up the data sheet of each zener available to see which met my needs.

There are similar types of numbering for transistors, ICs and all other electronic components. My question is that, is it possible to identify the characteristics of a particular component by looking at its numbering and not the data sheet? For example, if I say a Zener is 1N5408, as a beginner, I understand nothing but that it is a Zener diode, and then I've to look at the data sheet for other characteristics. Is that the case with everyone? What do you do when you want a particular component with some specifications in particular? Do you just Google it up, or is their some systematic approach to this?

Moreover, can anyone provide me a table by which I shall be able to understand which serial number of components refers to what? For example, BAV99 is a dual diode, whereas BT146 is a triac. How can I understand at the first sight that the given serial number refers to a diode, transistor or such other components? What is their systematic numbering process, if any?

• no, it means its a general purpose rectifier. A zener is something very specific, a diode designed to operate in its avalanche region with a more predictable voltage – JonRB Oct 25 '17 at 18:33
• The 1N and 2N numbering schemes have no more system than counting the leads. The B… numbering scheme actually has a system, starting with the B, which means Silicium. That scheme is called en.wikipedia.org/wiki/Pro_Electron – Janka Oct 25 '17 at 18:40
• No, it says 1N4733A et al. are zeners. – Janka Oct 25 '17 at 18:42
• No, it isn't. If 1Na is X and 1Nb is X, that doesn't mean all 1N are X. – Janka Oct 25 '17 at 18:45
• part numbering is utter chaos. Get used to it. Although there may be small islands of what look like sense, they don't generalise beyond their little islands. Just as you can't assume that all people called Gerald are accountants, you can't assume that all components with an '08' in the part number can take 8 amps. – Neil_UK Oct 25 '17 at 19:08

To give you some hope, the 1N and 2N series refer to the number of junctions in the devices.

simulate this circuit – Schematic created using CircuitLab

• 1N will almost (just covering the exceptions) always mean a diode of some sort as they have only one PN junction.
• 2N refers usually to bipolar junction transistors which have two PN junctions.
• Here is a 3N187 - a dual insulated-gate field-effect transistor. It has four leads.

A web search found some 4N and 6N but they seem to be opto-couplers and I can't see the continuation of the 1N, 2N pattern.

See stephenvh's answer to Is there any reasoning behind component names? for further information.

• Woah. This is new to me. – efox29 Oct 25 '17 at 19:51
• OK I learned something too. 1N, 2N, never read this anywhere before. – Adam Eberbach Oct 25 '17 at 23:11

Part numbers make sense... in the sense that they are not completely random. But they aren't supposed to make sense to regular people who don't work with electronics on a daily basis. In most cases, parts are just called what the original manufacturer decided to call them, so predictably it's a mess.

If you know a bit of trivia regarding the part's history, sometimes you can tell. One example is the 7400 series - when you see the 74somethingssomething, you should immediately proclaim that some old-school boolean stuff must be going on (that tends to impress the newbies: "he must know about every single part number since the sixties!").

Sometimes the part number encoder some parameter (eg LM7805 are +5V regulators, LM7812 are +12V regulators, and LM7905 are -5V regulators), but it doesn't happen nearly as often as it should.

What I do when I want to look for a part with certain characteristics ("at least 1A, reverse breakdown voltage of 60V") is to use the parametric catalog of some online store.