Based on GOST 2.710-81. This page is not the original document. Translation may be inaccurate.
Elements of electrical circuits can have both a single-letter and two-letter designation.
1. The letters of the most common types of elements are given in Table 1.
Table 1
| First letter of code (required) | Group kinds of elements | Examples of kinds of elements |
| А | Devices | Amplifiers, telecontrol devices, lasers, masers |
| В | Converters of non-electrical quantities to electrical (other than generators and power supplies) or vice versa, analog or multi-digit converters or sensors for indicating or measuring | Loudspeakers, microphones, thermoelectric sensors, ionizing radiation detectors, pickups, selsyns |
| С | Capacitors | |
| D | Integrated circuits, microassemblies | Integrated analog and digital circuits, logic elements, memory devices, delay devices |
| Е | Different elements | Lighting devices, heating elements |
| F | Arresters, fuses, protective devices | Discrete protection elements for current and voltage, fuses, arresters |
| G | Generators, power supplies, quartz oscillators | Batteries, electrochemical and electrothermal sources |
| Н | Indicating and signaling devices | Sound and light signaling devices, indicators |
| К | Relays, contactors, starters | Current and voltage relays, electrothermal relays, time relays, contactors, magnetic starters |
| L | Inductors, chokes | Chokes for fluorescent lighting |
| М | Motors | AC and DC motors |
| Р | Devices, measuring equipment | Indicating, recording and measuring devices, counters, clocks |
| Q | Switches and disconnectors in power circuits | Disconnectors, short-circuiting switches, circuit breakers (power) |
| R | Resistors | Variable resistors, potentiometers, varistors, thermistors |
| S | Switching devices in control, signaling and measuring circuits | Switches, switches triggered by various influences |
| T | Transformers, autotransformers | Current and voltage transformers, stabilizers |
| U | Converters of electrical quantities to electrical, communication devices | Modulators, demodulators, discriminators, inverters, frequency converters, rectifiers |
| V | Electrovacuum, semiconductor devices | Electronic lamps, diodes, transistors, thyristors, zener diodes |
| W | Lines and elements of ultrahigh frequency, antennas | Waveguides, dipoles, antennas |
| X | Connections contact | Pins, nests, collapsible connections, current collectors |
| Y | Mechanical devices with electromagnetic drive | Electromagnetic couplings, brakes, cartridges |
| Z | Terminal devices, filters, limiters | Modeling line, quartz filters |
2. Examples of two-letter codes are given in Table 2
Table 2
| First letter of code (required) | Group kinds of elements | Examples of kinds of elements | Two-letter code |
| А | Device (general designation) | ||
| В | Converters of non-electrical quantities to electrical (other than generators and power supplies) or vice versa, analog or multi-digit converters or sensors for indicating or measuring | Loudspeaker | ВА |
| The magnetostrictive element | ВВ | ||
| The ionizing radiation detector | BD | ||
| Selsyn receiver | BE | ||
| Phone (capsule) | ВF | ||
| Celsin sensor | ВС | ||
| Thermal sensor | ВК | ||
| Photocell | BL | ||
| Microphone | ВМ | ||
| Pressure meter | ВР | ||
| Piezoelement | BQ | ||
| Tachogenerator | BR | ||
| Pickup | BS | ||
| Speed sensor | BV | ||
| C | Capacitors | ||
| D | Integrated circuits, microassemblies | Integrated analog circuit | DA |
| Integrated circuit, digital, logic element | DD | ||
| Storage devices | DS | ||
| Delay device | DI | ||
| Е | Different elements | Heating element | ЕК |
| Lighting lamps | EL | ||
| Pyropatron | ЕТ | ||
| F | Arresters, fuses, protective devices | Discrete instantaneous protection element | FA |
| Discrete protection element for electrical current, inertial action | FP | ||
| Fuse | FU | ||
| Discrete voltage protection element, arrester | FV | ||
| G | Generators, power supplies | Battery | GB |
| H | Indicating and signaling devices | Sound alarm device | HA |
| Indicator symbolic | HG | ||
| Light signal device | HL | ||
| К | Relays, contactors, starters | Current relay | КА |
| Indicative relay | КН | ||
| Electrothermal relay | КК | ||
| Contactor, magnetic starter | KM | ||
| Time-delay relay | КТ | ||
| Voltage relay | KV | ||
| L | Inductors, chokes | Fluorescent lighting choke | LL |
| М | Motors | ||
| Р | Devices, measuring equipment Note. The combination of PE is not allowed | Ammeter | РА |
| Pulse counter | PC | ||
| Cymometer | PF | ||
| Active energy meter | PI | ||
| Counter of reactive energy | РК | ||
| Ohmmeter | PR | ||
| Recording device | PS | ||
| Clock, time meter | PT | ||
| Voltmeter | PV | ||
| Wattmeter | PW | ||
| Q | Switches and disconnectors in power circuits (power supply, equipment supply, etc.) | Automatic switch | QF |
| Short-circuit switch | QK | ||
| Disconnector | QS | ||
| R | Resistors | Thermistor | RK |
| Potentiometer | RP | ||
| Measuring shunt | RS | ||
| Varistor | RU | ||
| S | Switching devices in control, signaling and measuring circuits Note. The designation SF is used for devices that do not have power-circuit contacts | Switch | SA |
| Push Button Switch | SB | ||
| Automatic switch | SF | ||
| Switches triggered by various actions: | |||
| Level | SL | ||
| Pressures | SP | ||
| Position | SQ | ||
| Rotational speed | SR | ||
| Temperature | SK | ||
| Т | Transformers, autotransformers | Current transformer | TA |
| Electromagnetic stabilizer | TS | ||
| Voltage transformer | TV | ||
| U | Communication devices Converters of electrical values in electrical | Модулятор | UB |
| Demodulator | UR | ||
| Discriminator | UI | ||
| Frequency converter, inverter, frequency generator, rectifier | UZ | ||
| V | Electrovacuum and semiconductor elemets | Diode, zener diode | VD |
| Electrovacuum elemet | VL | ||
| Transistor | VT | ||
| Thyristor | VS | ||
| W | Lines and elements of microwave Antennas | Coupler | WE |
| Short-circuit switch | WK | ||
| Ventil | WS | ||
| Transformer, phase shifter | WT | ||
| Attenuator | WU | ||
| Antenna | WA | ||
| X | Connections contact | Current collector, the sliding contact | XA |
| Pin | XP | ||
| Socket | XS | ||
| Collapsible connection | XT | ||
| High frequency connector | XW | ||
| Y | Mechanical devices with electromagnetic drive | Electromagnet | YA |
| Brake with electromagnetic drive | YB | ||
| Coupling with electromagnetic drive | YC | ||
| Electromagnetic cartridge | YH | ||
| Z | End devices, filters Limiters | Limiter | ZL |
| Quartz filter | ZQ | ||
1. Letter codes to indicate the functional purpose of the elements listed in Table 1
Table 1
| Literal code | Functional purpose | Literal code | Functional purpose |
| А | Auxiliary | N | Measuring |
| В | Direction of movement (forward, backward, up, down, clockwise, counter-clockwise) | Р | Proportional |
| C | Counting | Q | Status (start, stop, limit) |
| D | Differentiating | R | Return, Reset |
| F | Protective | S | Memorization, recording |
| G | Test | T | Synchronization, delay |
| Н | Signal | V | Speed (acceleration, deceleration) |
| I | Integrating | W | Addition |
| К | Pushing | X | Multiplication |
| M | Main | Y | Analog |
| Z | Digital | ||