# 131 series integrated circuits

> series of Soviet TTL logic circuits

**Wikidata**: [Q115861500](https://www.wikidata.org/wiki/Q115861500)  
**Source**: https://4ort.xyz/entity/131-series-integrated-circuits

## Summary
The 131 series integrated circuits are a Soviet model series of transistor–transistor logic (TTL) integrated circuits that were based on the Western 7400 series. These circuits were manufactured in the Soviet Union and used the dual in-line package format.

## Key Facts
- Instance of: integrated circuit series
- Subclass of: transistor–transistor logic, integrated circuit
- Based on: 7400 series
- Country of origin: Soviet Union
- Package type: dual in-line package
- Aliases: 74H
- Complies with: Soviet integrated circuit designation
- Wikimedia sitelink count: 1
- Wikipedia languages: commons
- Commons category: 131 series integrated circuits

## FAQs
### Q: What are 131 series integrated circuits?
A: The 131 series are Soviet TTL logic integrated circuits that were developed as counterparts to Western 7400 series chips. They were manufactured in the Soviet Union and used similar functionality to their Western counterparts.

### Q: What package type do 131 series ICs use?
A: 131 series integrated circuits use the dual in-line package (DIP) format, which was a standard package type for TTL logic chips during that era.

### Q: How are 131 series ICs related to Western chips?
A: The 131 series are based on the Western 7400 series of TTL logic integrated circuits, meaning they share similar functionality and specifications but were manufactured to Soviet standards and designations.

## Why It Matters
The 131 series integrated circuits represent an important chapter in the history of Soviet electronics manufacturing and the Cold War technological landscape. During a period when the Soviet Union was largely isolated from Western technology, these chips demonstrate how Soviet engineers reverse-engineered and produced functional equivalents of Western TTL logic families. This allowed Soviet electronics industries to develop computers, control systems, and other digital devices without relying on Western imports. The 131 series played a crucial role in enabling Soviet technological development in computing and automation during the latter half of the 20th century, contributing to the growth of Soviet electronics manufacturing capabilities and reducing dependence on Western technology.

## Notable For
- Being the Soviet counterpart to the widely-used Western 7400 series TTL logic chips
- Enabling Soviet electronics industry to develop digital systems independently of Western technology
- Using the standardized dual in-line package format for compatibility with existing designs
- Following Soviet integrated circuit designation standards while maintaining Western functionality
- Representing successful reverse-engineering of Western TTL technology during the Cold War era

## Body
### Technical Specifications
The 131 series integrated circuits were designed to be functional equivalents of the Western 7400 series TTL logic chips. They operated using transistor–transistor logic, which was the dominant technology for digital integrated circuits during the 1960s through 1980s. The series included various logic functions such as gates, flip-flops, counters, and other digital building blocks.

### Manufacturing and Design
These circuits were manufactured in the Soviet Union following Soviet integrated circuit designation standards. The "131" prefix was part of the Soviet system for categorizing integrated circuits. Despite being produced in a different country and under different political circumstances, the 131 series maintained compatibility with Western TTL logic levels and timing characteristics.

### Package and Physical Characteristics
The 131 series used the dual in-line package (DIP) format, which was the standard package type for TTL logic chips of that era. This package style featured two parallel rows of pins that could be inserted into through-hole printed circuit boards. The DIP format made these chips compatible with existing circuit board designs and manufacturing processes.

### Historical Context
The development of the 131 series occurred during the Cold War when technological exchange between the Soviet Union and Western countries was limited. These chips represent how Soviet engineers were able to analyze, understand, and reproduce Western technology despite political and economic barriers. The series demonstrates the Soviet Union's capability to develop indigenous semiconductor technology while maintaining compatibility with Western standards.