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Description: | SEMICS SB 231 5290 UK (stencilled inn blue on the outer casing). MANU Semiconductors Limited. 1960 Cheney Manor, Swindon, Wiltshire, England. DES after SHOCKLEY,William,Bradford. 1947 Bell Telephone Laboratories, New Jersey, The United States of America. This is a Semiconductors' SB 231 germanium p-n-p surface barrier transistor. Called an entertainment receiver transistor this device was designed for RF (radio frequency) operations in broadcast receivers up to 30 MHz. It could be used as an; amplifier, frequency mixer, oscillator, self-oscillating mixer, and as a high gain IF (intermediate frequency) amplifier.
A transitor is the solid state version of a triode valve it operates a switch, gate or amplifier. Transistors are made of a variety of solid crystalline metallic or transition elements, such as germanium or silicon. The most important thing about them is that although they conduct electricity they are said to be reluctant conductors i.e. they are not as good as metals such as copper. They posess electrical conductivities greater than insulators but less than good conductors.
A junction transistor is constructed of two layers of an n-type semiconductor sandwiched between two layers of a p-type semiconductor. The n type acts as the base, which separates the emitter and collector. The base is analogous to the control grid in a triode valve. The p type semiconductor, in two layers, sandwiching the base acts as emitter and collector. The emitter being the source of electrons, analagous to the filament (cathode) in a triode valve and the collector, analagous to the plate (anode) in a triode valve.
The conducting properties of the germanium semiconductor is usually modified by the addition, called doping, of very small amounts of other elements such as arsenic. | License: | http://www.hmag.gla.ac.uk/spirit/rights/ | Publisher: | Hunterian Museum and Art Gallery, University of Glasgow | Rights holder: | Hunterian Museum and Art Gallery, University of Glasgow | Subjects: | SCIENTIFIC COLLECTION : | Source: | Hunterian Museum | Creator: | Hunterian Museum and Art Gallery, University of Glasgow | Identifier: | http://www.huntsearch.gla.ac.uk/cgi-bin/... | Language: | en-GB | Go to resource |
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