 Left to right: octal (top and bottom view), loctal, and miniature (top and side view) sockets. An early transistor socket and an IC socket are included for comparison. Tube sockets were ubiquitous in early electronic equipment to allow vacuum tubes (also known as valves) to be easily removed for testing and replacement. Tubes often failed because the filament burned out, but other failure modes were common. In the heyday of radio and early television, it was common to find a vacuum tube tester in local drug stores, which also sold replacement tubes. Download high resolution version (1087x532, 202 KB)Various vacuum tube sockets. ...
Download high resolution version (1087x532, 202 KB)Various vacuum tube sockets. ...
In electronics, a vacuum tube (American English) or (thermionic) valve (British English) is a device generally used to amplify, or otherwise modify, a signal. ...
Tube sockets were typically mounted in holes on a sheet metal chassis and wires or other components were hand soldered to lugs on the underside of the socket. In the 1950s printed circuit boards were introduced and tube sockets were developed whose contacts could be soldered directly to the printed wiring traces. Looking at the bottom of a socket, or, equivalently, a tube from its bottom, the pins were numbered clockwise, starting at an index notch or gap, a convention that has persisted into the integrated circuit era. A solder is a fusible metal alloy (often of tin and lead), with a melting point or melting range below 450°C (840°F) and is melted to join metallic surfaces, especially in the fields of electronics and plumbing, in a process called soldering. ...
// Events and trends The 1950s in Western society was marked with a sharp rise in the economy for the first time in almost 30 years and return to the 1920s-type consumer society built on credit and boom-times, as well as the height of the baby-boom from returning...
Close-up photo of one side of a motherboard PCB, showing conductive traces, vias and solder points for through-hole components on the opposite side. ...
Optical Microscope image of an integrated circuit showing defects in the aluminium layer deposition. ...
In the 1930's tubes often had the connection to the control grid, brought out though a metal cap on the top of the tube. This was conected by using a clip with an attached wire lead. An example would be the 6A7 pentagrid converter. Later, some tubes particularly those used as radio frequency (RF) power amplifiers or horizontal delection amplifiers in TV sets such as the 6DQ6 had the plate or anode lead protrude through the envelope. In both cases this allowed the tube's output circuitry to be isolated from the input (grid) circuit more effectively. In the case of the tubes with the plate brought out to a cap, this also allowed the plate to run at higher voltages (over 26,000 volts in the case of rectifiers for colour television such as the 3A3). An electrode used in Thermionic valves (tubes) used to modulate the flow of electrons in the cathode to anode or plate circuit. ...
During the valve (tube) era of radio, frequency conversion in superheterodyne receivers was typcally carried out by a hexode thermionic valve (tube), energised with the incoming signal, plus the local oscillator signal derived from an additional triode valve (tube). ...
Diagram of a zinc anode An anode (from the Greek άνοδος = going up) is the positive electrode in an electrolytic system or circuit. ...
Octal base
In 1935, RCA introduced a new type of tube base for their new metal envelope tubes, which they called an "Octal base". True to the name, it had 8 pins on an 11/16" pin circle, with a 5/16" diameter keyed locating prong or "spigot" in the center.When used on metal tubes, pin #1 was always reserved for a connection to the metal shell, which was grounded for shielding purposes.
The octal base soon caught on for conventional glass tubes as well, where the large central prong could also house and protect the "vacuum tip" of the glass tube. The eight available pins allowed more complex tubes to be constructed, including dual triodes, etc. The glass envelope of each octal vacuum tube (for example, the 6SN7) was cemented into a bakelite or plastic base with a hollow post in the center, surrounded by eight metal pins. The wire leads from the tube were soldered into the pins and the pinched-off glass nub through which the air was evacuated from the envelope fit into the post. The post had a protrusion along one side that matched the indexing slot in the socket so the tube could only be inserted in the correct orientation. 6SN7 is a dual triode vacuum tube, on an 8 pin octal base. ...
Bakelite is a brand named material based on the thermosetting phenol formaldehyde resin polyoxybenzylmethylenglycolanhydride, developed in 1907-1909 by Dr. Leo Baekeland. ...
Matching plugs were manufactured that let tube sockets be used as electrical connectors, though penurious experimenters would salvage the base from a burned out tube for this purpose. Octal sockets were used to mount other components, particularly electrical relays and octal-mount relays are still common. An electrical connector is a device for joining electrical circuits together. ...
Relay is also the name of a series of medium-altitude satellites; the first of which was launched in 1962. ...
A variant of the octal base, the loctal base (sometimes spelled "loktal"), was developed by Sylvania for ruggedized applications such as automobile radios. The pin geometry was the same as for octal, but the pins were thinner, the base shell was made of aluminum, and the center hole had an electrical contact that also clamped the tube in place. Loctal tubes were never that popular, and were only adopted widely by a handful of equipment manufacturers, most notably Philco, which used the tubes in many ordinary table radios. Loctal tubes are often difficult to remove from their sockets (look for a small indexing mark on the side of the base skirt and push the tube from that side to unlock). They are also prone to intermittent connections due to the short, thin base pins, which have a tendency to build up an oxidation layer.
Miniature tubes Miniature tubes (e.g. the 12AX7) were introduced around World War II. Wires protruding through the bottom of the glass envelope plugged directly into the socket -- there was no separate base. The pinched-off air evacuation nub was at the top of the tube, giving it its distinctive appearance. The wire pins were arranged in a circle with one pin missing, so the tube could only be plugged one way. Seven and nine pin tubes were common, though miniature tubes with more pins were later introduced. Miniature tube sockets often had a skirt that mated with a cylindrical shield that fit around the tube. Some shields incorporated a spring to hold the tube in place. These were used if the equipment was subject to vibration. 12AX7 is a miniature dual triode vacuum tube of high gain. ...
Other socket styles Vacuum tubes for high power or UHF applications often required custom socket designs. Subminiature tubes, introduced in the 1950s were often soldered directly to printed circuit boards. Sockets were made for early transistors, but quickly fell out of favor as their reliability became established. The same thing happened with early integrated circuits where sockets are now usually reserved for those devices that may be upgraded or used for the replacement of firmware. // Events and trends The 1950s in Western society was marked with a sharp rise in the economy for the first time in almost 30 years and return to the 1920s-type consumer society built on credit and boom-times, as well as the height of the baby-boom from returning...
Through hole transistors (tape measure marked in centimeters) The transistor is a solid state semiconductor device which can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. ...
In computing, firmware is software that is embedded in a hardware device. ...
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