The transistor is a ck722 nte102 germanium equivalent. One of the most popular of these was on page 9 a regenerative receiver, designed and built by mr. The mythical ck722 transistor was the result of an inspired program. K3561 datasheet nch transistor, vdss 500v toshiba, 2sk3561 datasheet, k3561 pdf, k3561 pinout, k3561 equivalent, k3561 data, circuit, k3561 schematic. Tentative data on the raytheon ck722 germanium junction transistor. So i would appreciate your help to tell me how i can replace those transistors, because i think they are very old. Raytheon transistor applications more than 50 practical. Everyday low prices and free delivery on eligible orders.
Aug 25, 2011 crossreferences are not magic, understanding of the circuit and a parametric search of the important parameters is much more reliable. This is is the philco 2n207, the first attempt at a commercial microminature transistor in the to23 package while electronics transistor corp put out their 2n207 in a big to5 but otherwise with very similar specifications. If you install the wrong polarity, the sandwich wont work. Thousands of radio kits using the ck722 were made in the 1950s and 1960s. Transistor application books for ck722 by raytheon size comparison and metal case colors of raytheon hearing aid transistors on the left and the ck721 blue and ck722 silveron the right. Choosing transistor replacements electronics notes. In the seventies, the superior silicon devices began to take over the hobby market. This is a pdf format of the well known hardware pinout book, which covers various computer, electrical and electronic item pinouts. The ck722 was the first lowcost junction transistor available to the general public. At the maximum voltage, also called a breakdown voltage bv, electrons. A transistor is a semiconductor device used to amplify and switch electronic signals and power. What follows is my own opinion and yes it is speculative, however it makes more sense to me than the bell labs claimed discove.
Transistor circuits books this section contains free e books and guides on transistor circuits, some of the resources in this section can be viewed online and some of them can be downloaded. Mar 11, 2010 many of the books and magazines from the mid 1950s and early 1960s, i read had circuits designed for ck722s. Full text of transistor techniques internet archive. Application of the ck722 pnp junctiontype transistor in singlestage and cascaded amplifiers and analytical bulletin of the committee of coordination of the telecommunications of the french union. Cross reference electronic circuits, tv schematics, audio. Transistor cross reference, equivalent and specification is very important for every electronic repairer the importance of transistor cross reference, datasheet, equivalent and specification. It seemed like the 2n35 was a popular npn transistor at the time. Understanding transistor cross reference, equivalent. Ck722 datasheet, cross reference, circuit and application notes in pdf format. Commercial grade transistors can run gains as high as 100 or more. Transistor the reader wiki, reader view of wikipedia.
Ck722 classic germanium transistor webpage and museum index. While conventional wisdom claims that the transistor was invented at bell labs in 1947, there may be more to that story. Return with us now to the halcyon days of germanium germanium transistor projects intrigued experimenters from the early days in the 1950s until the early 1970s. A great deal of information contained in this raytheon transistor book has been made available through. Free transistor circuits books download ebooks online. In the 1950s and 1960s, hundreds of hobbyist electronics projects based around the ck722 transistor were published in popular books and. A raytheon ck722 was actually a repackaged ck718 that didnt meet specifications. The data sheet is very important for every engineers and technicians because it can help them to find the nearest replacement for the components that they are. Here you can see all on 4 pages all my crystal radio circuit diagrams. Competitor cross reference cross reference data provided by on semiconductor product specialists and partminer. B688 datasheet pnp silicon power transistors mospec.
In the 1950s and 1960s, hundreds of hobbyist electronics projects based around the ck722 transistor were published in popular books and magazines. On the 30th of june a similar presentation was made to the mainstream and technical media. You wouldnt find a ck722 in any piece of consumer electronics. I once broke a leg off my ck722, i was a teenager and couldnt afford to buy another one, so i peeled the blue metal cover off and some gooey stuff, and there was a. I once broke a leg off my ck722, i was a teenager and couldnt afford to buy another one, so i peeled the blue metal cover off and some gooey stuff, and there was a smaller, silver.
In the 1950s and 1960s, hundreds of hobbyist electronics projects based around the ck722 transistor were published in popular books. A complete guide to semiconductor replacement and substitutions from the makers of photofactr service documentation. Design and application of transistor switching circuits. Transistor academic dictionaries and encyclopedias. A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. International transistor equivalents guide bernard babani. The rejected hearing aid transistors would be inside the metal cases of the ck721 and ck722. Redesign germanium transistor circuits, part 1 today. The 2n107 was a later transistor, than the ck722, but has always been a suggested sustitute for the ck722. Many of the books and magazines from the mid 1950s and early 1960s, i read had circuits designed for ck722s. It is necessary to ensure that the replacement transistor will be able to operate at the relevant frequencies, so a similar or slightly higher ft is advisable. There seems to be lots of nos russian pnp germanium transistors around for cheap. Texas instruments transistor and diode databook 1st ed 1973 datasheets for diodes from 1n251 on and transistors from 2n117 on acrobat 7 pdf 34.
When the raytheon ck722 transistor applications book appeared in 1955, the first few pages listed radio projects that could be built with the ck722. Welcome to daves homemade crystal radio schematic selector page. Finding transistor replacement can take you hours if you dont know the right method to do it. For classa operation, germanium devices require a nosignal bias of 0. Raytheon ck722 transistor introduced in 1953, the raytheon ck722 was the first commercial transistor available over the counter for hobbyists and experimenters. If more than a maximum voltage rating is applied to a transistor, it can be permanently damaged.
Ck722 datasheet, equivalent, cross reference search. Crossreferences are not magic, understanding of the circuit and a parametric search of the important parameters is much more reliable. Ic cross reference cross reference ci stk cross reference ci tda cross reference ci sharp cross reference hitachi audio ic cross reference and circuit applications smd cross reference and equivalent we make every effort to ensure that the material on this site is accurate, however we do not warrant or represent that the information is free. The information presented in on semiconductors cross reference tool is based on our best estimate of other manufacturers published information at the time that we collected this information. The story of the ck722 ck722 classic germanium transistor. Welcome to daves homemade tube radio schematic selector page. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. Norm krim selected radio shack to sell the ck721 and ck722 through their catalog. C1815 cross reference electronic circuits, tv schematics, audio. What would be a modern equivalent of the ck722 pnp germanium transistor. Cross reference universal transistor reference page 1. A voltage or current applied to one pair of the transistors terminals controls the current through another pair of terminals. The experimenters transistors, such as the 2n107 and the ck722, have gains of about 20. The importance of transistor cross reference, datasheet, equivalent and specification.
Understanding transistor circuits, august 1959 popular. Neither of these books feature raytheons semiconductor history in any. K3561 datasheet n ch transistor, vdss 500v toshiba. Buy international transistor equivalents guide bernard babani publishing radio and electronics books by michaels, adrian isbn. Sure, the 2n404 has more gain and less leakage, but it worked. Raytheon got into the act too, introducing their transistors, especially the ck722, to the hobbyist market with the publication, raytheon transistor applications, more than 50 practical circuits using raytheon ck722 transistors. These to23 package ones are clearly marked 2n207, one with a datecode of 6309, and the other 6350, so these are 50 years. A substitute transistor must have the same polarity, either pnp or npn, as the original.
More than 490,000 part numbers, type numbers, and other identifying numbers listed. History of the transistor wikipedia republished wiki 2. Transistor museum store construction projects point contact. The 2n63 is a direct electrical equivalent of the raytheon ck722 and the. The ck722 holds a unique place in the history of the transistor. Knowing how to substitute an alternate transistor type can speed up your. Hi guys, im in the half of engineering, so i dont have much experience yet. The transistor is the fundamental building block of both digital and analog integrated circuitsthe circuitry that governs the operation of computers, cellular phones, and all other modern electronics. C1815 cross reference electronic circuits, tv schematics. Here you can see all on 2 pages all my crystal radio circuit diagrams this is my homemade tube radio page. Your historic transistors, photos, descriptive text and storage envelopes. If i ever manage to aquire one, id keep it aside as a collectors item anyway. B688 datasheet pnp silicon power transistors mospec, 2sb688 datasheet, b688 pdf, b688 pinout, b688 equivalent, data, circuit, output, b688 schematic.
Although the boys never came across one of norm krims ck722 transistors in their original adventures, it. The original transistor might need special ordering, or be discontinued and unavailable. Complete howtodoit instructions paperback 1955 by raytheon manufacturing co. For smallsignal npn devices, substitute a 2n2222a silicon transistor. History of the transistor wikimili, the free encyclopedia. Searching the right transistor for substitution is a skill, if you replace wrong specifications of transistor. Ive acquired an old ratheon ck722 transistor several years ago. The equivalent classa bias for silicon devices is 0.
Raytheon released the ck722 and the higher specification ck721 in 1953. Ive had good luck using 2n404s as ck722 subs but 2n404s have a bit more gain, etc than ck722s. Understanding transistor replacement, substitution and information is very important for a electronic repairer. The ck722 was the most popular transistor ever made. Even for the same transistor type the terminal assignment can vary normally indicated by a suffix letter to the part number, q.
Transistor semiconductor history texas instruments rca bell laboratories. A voltage or current applied to one pair of the transistors terminals changes the current flowing through another pair of terminals. More time is spent figuring out which one to replace and, sometimes, what to replace it with. Aug 01, 2016 raises collector load reactance at rf to increase stage gain.
As i stated above, just about any pnpge transistor will work in place of the ck722, as they are all better transistors. Semiconductor transistor, diode, ic cross reference. So called equivalent parts, or nte replacements, may not work at all in some cases, because they were worse in some spec, or the circuit was designed with the assumptions that the part had a fairly low bandwidth. It seemed like often, ck722s were paired with 2n35s in circuits. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit. I have no idea what that is at the current rate, but it is expensive. I am also developing another ck722 transistor applications book, 50 years of the ck722. A transistor is a threeterminal semiconductor device that can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. The circuit is that of a conventional feedback audio oscillator. The first highfrequency transistor was the surfacebarrier germanium transistor developed by philco in 1953, capable of operating up to 60 mhz. By the way, the ck722 became the most popular transistor in the world, but inside every one was a reject from the hearing aid industry. I can generally find 2n404s on the net for less than nte102s. When ive built a circuit in the past that called for a ck722, ive found that a 2n404 has worked as a substitute for me.
Raytheon transistor applications more than 50 practical circuits using raytheon ck722 transistors. Understanding transistor replacement, substitution and. All electronic repairers should know how to read the transistor cross reference equivalent book if they want to succeed in electronic repairs. The boys experiment with a ck722 their first transistor. Transistor packages are mainly standardized, but the assignment of a transistor s functions to the terminals is not. It was an instant success spurring the creation of hundreds of kits and a large number of ck722 circuits over the next several years. Build germanium transistor projects with silicon transistors. These were made by etching depressions into an ntype germanium base from both sides with jets of indiumiii sulfate until it was a few tenthousandths of an inch thick. Select a replacement transistor with equivalent ft. The ck722 was designed for hobbyists and ree was an electronics retail and repair outfit. A transistor is a logical choice for dc to ac conversion be cause of its efficiency and small size. If it helps to you, i need them for a pacemaker, this one. The teacher noticed the thick book on shakespeare that carl. I can never find any cross reference info for them, however.
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