BNC connector
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BNC
Male 50 ohm BNC connector
Type
RF coaxial connector
Production history
Designer
Paul Neill, Carl Concelman, & Octavio M.
Salati
Designed
Patented 1951
Manufacturer Various
General specifications
Diameter
Male:0.570in (1.45cm)
Female:0.436in (1.11cm)
(outer, typical)
Cable
Coaxial
Passband
Typically 0-3GHz
The BNC connector (Bayonet Neill-Concelman connector) is a common type of RF
connector used for the coaxial cable which connects much radio, television, and other
radio-frequency electronic equipment.
It is usually applied for frequencies below 3GHz [1] and below 500 Volts. [2]
Contents
[hide]

1 Use

2 Name and origin
o 2.1 Origin
3 Types and compatibility
o 3.1 Types

3.2 Mechanical compatibility
o 3.3 Electrical compatibility
4 BNC inserter/remover tool
5 Similar connectors
o 5.1 BNC equivalents and variants
 5.1.1 SR-50 and SR-75
 5.1.2 TNC (Threaded Neill–Concelman)
 5.1.3 Twin BNC or twinax
 5.1.4 Triaxial
o


o
5.2 Other connectors
 5.2.1 N and C connectors



5.2.2 High voltage connectors
5.2.3 Miniature connectors
6 References
[edit] Use
BNC Tee Connectors with terminators
The BNC connector is used for signal connections such as:




analog and serial digital interface video signals
amateur radio antennas
aviation electronics (avionics)
test equipment.
It is an alternative to the RCA connector when used for composite video on commercial
video devices, although many consumer electronics devices with RCA jacks can be used
with BNC-only commercial video equipment via a simple adapter. BNC connectors were
commonly used on 10base2 thin Ethernet networks, both on cable interconnections and
network cards. The TNC (threaded) connector is used for stable performance at higher
frequencies than used with the BNC connector.
BNC connections can also be found in recording studios. Digital recording equipment uses
the connection for synchronization of various components via the transmission of word
clock timing signals.
[edit] Name and origin
[edit] Origin
The connector was named after its bayonet mount locking mechanism and its inventors,
Paul Neill and Carl Concelman.[1] Neill worked at Bell Labs and also invented the N
connector; Concelman worked at Amphenol and also invented the C connector.
The basis for the development of the BNC connector was largely the work of Octavio M.
Salati, a graduate of the Moore School of Electrical Engineering of the University of
Pennsylvania.[3] In 1945, while working at Hazeltine Electronics Corporation, he filed a
patent for a connector for coaxial cables that would minimize wave reflection/loss.[4][5]
[edit] Types and compatibility
[edit] Types
BNC connectors exist in 50 and 75 ohm versions, matched for use with cables of the same
characteristic impedance. The 75 ohm types can sometimes be recognized by the reduced
or absent dielectric in the mating ends. The 50 and 75 ohm connectors are typically
specified for use at frequencies up to 4 and 2GHz respectively.
75 ohm BNC Connectors are primarily used for video and DS3 Telco central office
applications[clarification needed], whereas 50 ohm are used for data and RF. The BBC had a
convention that BNC connectors used for video were always 50 ohm, maybe because an
accidentally connected 50 ohm plug would damage a 75 ohm socket.[dubious – discuss] Many VHF
receivers used 75 ohm antenna inputs, so they often used 75 ohm BNC connectors.
[edit] Mechanical compatibility
The different versions are designed to mate with each other,[2] and a 75 ohm and a 50 ohm
BNC connector which both comply with the 1978 standard, IEC 169-8, will mate
non-destructively. At least one manufacturer [6] claims very high reliability for the
connectors' compatibility.
[edit] Electrical compatibility
At frequencies below 10MHz the impedance mismatch between a 50 ohm connector or
cable and a 75 ohm one has negligible effects.[7] BNC connectors were thus originally made
only in 50 ohm versions, for use with any impedance of cable. Above this frequency,
however, the mismatch becomes progressively more significant and can lead to signal
reflections.
[edit] BNC inserter/remover tool
A BNC inserter/remover tool also called a BNC tool, BNC extraction tool or BNC apple
corer, is used to insert or remove BNC connectors in high density or hard-to-reach
locations, such as densely wired patch panels in broadcast facilities like central apparatus
rooms.
They are usually light weight, made with stainless steel, and have screw driver type plastic
handle grips for applying rotating torque. Their shafts are usually double the length of a
standard screw driver.
BNC tools help in safely, efficiently and quickly accessing BNC connectors, in jack fields.
Using BNC tools also minimizes risk of accidentally disconnecting other connectors close
by.
[edit] Similar connectors
Triaxial BNC connector
[edit] BNC equivalents and variants
[edit] SR-50 and SR-75
In the USSR, BNC connectors were copied as SR-50 (СР-50 in Cyrillic) and SR-75 (С
Р-75 in Cyrillic) connectors. As a result of recalculating from imperial to metric
measurements their dimensions differ slightly from those of BNC. They are however
generally interchangeable with them, sometimes with force applied.
[edit] TNC (Threaded Neill–Concelman)
A threaded version of the BNC connector, known as the TNC connector (for Threaded
Neill-Concelman) is also available. It has superior performance to the BNC connector at
microwave frequencies.
Main article: TNC connector
[edit] Twin BNC or twinax
Twin BNC (also known as twinax) connectors use the same bayonet latching shell as an
ordinary BNC connector but contain two independent contact points (one male and one
female), allowing the connection of a 78 ohm or 95 ohm shielded differential pair such as
RG-108A.[8] They can operate up to 100MHz and 100 volts. They cannot mate with
ordinary BNC connectors.
[edit] Triaxial
Triaxial (also known as triax) connectors are a variant on BNC which carry both a signal
and guard as well as ground conductor. These are used in sensitive electronic measurement
systems, particularly of Keithley manufacture.[citation needed] Early ones were designed with just
an extra inner conductor, but later triaxial connectors also include a three-lug arrangement
to rule out an accidental forced mating with a BNC connector. Adaptors exist to allow
some interconnection possibilities between triax and BNC connectors.
[edit] Other connectors
[edit] N and C connectors
Historically these were the predecessors of the BNC, and they are much larger. The N
connector was invented by Paul Neill and the C connector by Carl Concelman, the two
inventors of the BNC.
Main article: N connector
[edit] High voltage connectors
For higher voltages (above 500 V), MHV and SHV connectors are typically used. MHV
connectors are easily mistaken for BNC type, and can be made to mate with them by brute
force. The SHV connector was developed as a safer alternative, and will not mate with
ordinary BNC connectors.
Main article: MHV connector
Main article: SHV connector
[edit] Miniature connectors
BNC connectors are commonly used in electronics, but they are replaced by LEMO 00
miniature connectors which allow for higher densities. In video broadcast industry, the
DIN 1.0/2.3 and the HD-BNC connector are used for higher density products.
[edit] References
Wikimedia Commons has media related to: BNC connectors
1.
^ a b Thomas H. Lee ,Planar microwave engineering: a practical guide to theory,
measurement, and circuits, Volume 1 Cambridge University Press, p. 111 (2004). ISBN
0521835267
a b
2.
^
BNC Connector specifications, Amphenol Connex
3.
^ BSEE 1936, PhD 1963.
4.
^ The patent was granted in 1951.
5.
^ Electrical connector. US Patent 2,540,012 by Octavio M. Salati
6.
^ Canford. "In over 15 years and many million BNC connectors we have no first
hand experience of incompatibility between 50 ohm and 75 ohm types, other than
extremely rare (and very obvious) manufacturing faults."
7.
^ BNC Connectors, The Canford Group
8.
^ Amphenol RF - Twin BNC connector series
[hide]v · d · eRF connectors (coaxial)
APC-7· BNC· C· F· FME· Hirose U.FL· IPX· Motorola· MCX· MMCX· N· QLS· QMA/QN·
RCA· SMA· SMB· SMC· Twin-lead· TNC· TV aerial plug· UHF / Mini-UHF
Variations and alternate names: 2.9 mm (SMA)· 7 mm· Triax / Triaxial· Twin BNC /
Twinax (BNC)· IPEX · MHF · AMC (UFL)· SnapN· RP-TNC· RP-SMA
Old or seldom used: EIA· GR· LEMO 00· Musa
See also: Radio frequency· Radio spectrum· Audio and video connectors· Audio and
video interfaces and connectors
[show]v · d · eAudio and video connectors
[show]v · d · eAudio and Video Interfaces and Connectors
Analog
Interface: PC System Design
Guide Connectors: TRS 3.5mm
Interface: S/PDIF Connectors:
Digital RCA Jack (Coaxial), TOSLINK
(Optical), BNC
Interface: VGA Connectors:
DB-15 • Interface: Composite
Connectors: RCA jack yellow •
Interface: S-Video Connectors:
Mini-DIN 4 Pin • Interface:
Analog
Component Connectors: RCA
Jacks × 3 • Interface:
Composite, S-Video, and
Component Connectors: VIVO
using Mini-DIN 9 Pin
Digital and Interface: DVI Connectors: DVI
Analog
Interface: HDMI Connectors: HDMI
Digital connector • Interface: DisplayPort
Connectors: DisplayPort connector
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Categories: Coaxial connectors
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