Pro Electron or EECA is the European type designation and registration system for active components (such as semiconductors, liquid crystal displays, sensor devices, electronic tubes and cathode ray tubes).
Pro Electron was set up in 1966 in Brussels, Belgium. In 1983 it was merged with the European Electronic Component Manufacturers Association (EECA) and since then operates as an agency of the EECA.
The goal of Pro Electron is to allow unambiguous identification of electronic parts, even when made by several different manufacturers. To this end, manufacturers register new devices with the agency and receive new type designators for them.
Designation system
Examples of Pro Electron type designators are: AD162 – Germanium power transistor for audio frequency use BY133 – Silicon rectifier BZY88C5V1 – Silicon 5.1 volt Zener diode CQY97 – light emitting diode ECC83 – 6.3 volt heater noval dual triode A63EAA00XX01 – Color TV picture tube SAA1300 – Digital integrated circuit
Pro Electron took the popular European coding system in use from around 1934 for valves (tubes), i.e. the Mullard–Philips tube designation, and essentially re-allocated several of the rarely used heater designations (first letter of the part number) for semiconductors. The second letter was used in a similar way to the valves naming convention: "A" for signal diode, "C" for low-power bipolar transistor or triode, "D" for high-power transistor (or triode), and "Y" for rectifier, but other letter designations did not follow the vacuum tube mode so closely.
The three digits (or letter followed by two digits) after the first two letters were essentially a sequence number, with (at first) a vestige of the valve-era convention that the first one or two digits would indicate the base (package) type in examples such as in this family of general-purpose transistors:
... where x may be: 7 for high voltage 8 for general purpose 9 for low noise/high gain
Pro Electron naming for transistors and Zener diodes has been widely taken up by semiconductor manufactures around the world. Pro Electron naming of integrated circuits, other than some special (e.g. television signal-processing) chips, did not greatly take hold (even in Europe). Other popular designation systems were used for many integrated circuits.
Differences between Pro Electron and earlier valve-naming conventions
Unlike the tube naming convention, if there are two transistors in a single envelope, the type letter was never repeated - so a dual NPN RF transistor might get a type "BFM505" rather than something like "BFF505" for instance. Although some of the most popular devices conform to a pattern of serial numbers that identified package type and polarity, many do not. The letters assigned for the second character of transistor and diode type numbers differ in several ways, e.g. "B" tends to be used for dual varicap diodes "L" in the context of transistors designates RF power (transmitting) transistors; for valves it meant a high-power pentode tube (the usual choice for power RF) "Z" is used for semiconductor Zener diodes instead of (full-wave) rectifier valves (tubes).
Frequently used first letters in European active devices
A Germanium (or any semiconductor with junctions in a material with a band gap of 0.6 to 1.0eV) B Silicon (or band gap of 1.0 to 1.3eV) C III-V semiconductors with a band gap of 1.3eV or more, like gallium arsenide in LEDs D may be... Semiconductors with a band gap less than 0.6eV, such as indium antimonide in infrared detectors (rarely used), or (Mullard–Philips) 1.4V (or less) filament tubes E (Mullard–Philips) tubes with a 6.3V heater F Digital integrated circuits P (Mullard–Philips) tubes for a 300mA series heater supply R Devices without junctions, e.g. cadmium sulfide in a photoresistor S Solitary digital integrated circuits T Linear integrated circuits U may be... (Mullard–Philips) tubes for a 100mA series heater supply, or Mixed digital/analogue integrated circuits
Electron tubes
See Mullard–Philips tube designation for details. A brief summary of just the more common letters is: ECC81 / \ \\__ last digit(s)=serial number / \ \__ first digit(s)=base (3=8pin 8,18,80=Noval (B9A), 9=Mini 7-pin (B7G) / \___ one letter per valve unit in the tube: D=1.4v or less A=single-diode (low power) E=6.3v* B=double-diode (usually shared cathode, but not always) P=300mA C=triode U=100mA F=pentode (low power) L=pentode (high power) Y=Single-phase rectifier Z=Full-wave rectifier * Note: some 6.3 volt heater types have a split heater allowing series (12.6 volt; the default for Noval pins 4 to 5) or parallel (6.3 volt) operation.