# 851 series integrated circuits

> two low-noise hybrid amplifiers for heat-seeking heads

**Wikidata**: [Q130550561](https://www.wikidata.org/wiki/Q130550561)  
**Source**: https://4ort.xyz/entity/851-series-integrated-circuits

## Summary  
The 851 series integrated circuits are Soviet hybrid integrated circuits designed as low-noise amplifiers for infrared homing systems, specifically used in heat-seeking missile guidance. These components were manufactured by Girikond and comply with Soviet IC naming conventions. They represent specialized electronics tailored for military applications during the Cold War era.

## Key Facts  
- Instance of: Integrated circuit series, hybrid integrated circuit, electronic amplifier  
- Country of origin: Soviet Union  
- Manufacturer: Girikond  
- Used in: Infrared homing (heat-seeking) systems  
- Complies with: Soviet integrated circuit designation standards  
- Subclass of: Hybrid integrated circuit, electronic amplifier  
- Commons category: 851 series integrated circuits  
- Image: [851УН2 Girikond](https://commons.wikimedia.org/wiki/Special:FilePath/851УН2_Гириконд_(1).jpg)  
- Wikidata description: Two low-noise hybrid amplifiers for heat-seeking heads  

## FAQs  
### Q: What is the 851 series integrated circuit used for?  
A: The 851 series integrated circuits are used in infrared homing systems, particularly in heat-seeking missile guidance. They function as low-noise amplifiers to enhance signal detection from thermal targets.

### Q: Who manufactured the 851 series integrated circuits?  
A: The 851 series was manufactured by Girikond, a Soviet-era electronics producer specializing in hybrid integrated circuits for defense applications.

### Q: Are the 851 series ICs digital or analog?  
A: The 851 series consists of analog hybrid integrated circuits, specifically designed as electronic amplifiers for signal processing in infrared sensors.

## Why It Matters  
The 851 series integrated circuits played a critical role in the development of Soviet infrared-guided weaponry during the Cold War. As part of the broader effort to miniaturize and optimize electronic systems for military use, these hybrid ICs enabled more reliable and sensitive heat-seeking capabilities in guided missiles. Their design reflects the technological priorities and constraints of Soviet electronics manufacturing, offering insight into how the USSR approached precision signal processing in defense systems. Though limited in public documentation, their existence underscores the parallel evolution of semiconductor technology outside Western markets.

## Notable For  
- Being purpose-built for infrared homing applications in military systems  
- Compliance with Soviet IC designation standards, indicating formal integration into state defense programs  
- Manufacture by Girikond, a specialized Soviet hybrid IC producer  
- Representation of Cold War-era advancements in analog hybrid circuitry for signal amplification  

## Body  

### Overview  
The 851 series integrated circuits are a set of hybrid electronic components developed in the Soviet Union for use in infrared (IR) homing systems. These circuits serve as low-noise amplifiers, enhancing weak signals received from heat-emitting targets such as aircraft or vehicle engines.

### Technical Classification  
- **Instance of**: Integrated circuit series, hybrid integrated circuit, electronic amplifier  
- **Subclass of**: Hybrid integrated circuit — combines discrete semiconductors and passive elements on a shared substrate  
- **Compliance**: Follows the Soviet system for integrated circuit nomenclature  

### Manufacturer and Origin  
- **Manufacturer**: Girikond (Гириконд), a Soviet enterprise focused on hybrid microelectronics  
- **Country**: Soviet Union  
- **Designation Standard**: Aligns with official Soviet IC part numbering practices  

### Application  
- **Primary Use**: Infrared homing systems, commonly found in air-to-air or surface-to-air guided missiles  
- **Function**: Amplify faint IR sensor signals while minimizing noise interference  

### Documentation and Visibility  
- **Wikidata Entry**: Described as “two low-noise hybrid amplifiers for heat-seeking heads”  
- **Wikipedia Presence**: Limited to Wikimedia Commons under the category "851 series integrated circuits"  
- **Image Resource**: Available via Wikimedia Commons showing an example labeled 851УН2  

### Legacy and Context  
As part of the USSR's efforts to develop self-contained guidance systems, the 851 series represents a niche but vital component within military avionics. While not widely documented in open literature, its classification as a hybrid IC highlights the diversity of approaches taken in global semiconductor development during the mid-to-late 20th century.