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-Joe Sousa

Last updated 11-19-2017

This web page was formerly hosted at

But this Comcast hosting service was discontinued.

DM160 vfd Triode in Phase Shift oscillator shows 8 octants

A groovy wavy way to make a phase shift oscillator.

Neon plasma beat_wave

How to have too much fun lighting up a stick with 20 Neon bulbs with beat frequencies between 60Hz and 61Hz , or 60Hz and 121Hz. The second frequency is adjustable and the 60Hz comes from the power line.

Precise decibel monitoring with Eye tubes Quicktime movies

Old EM84/6FG6 logarithmic responding eye tubes get a face lift and gain accuracy with a dB graduated electronic scale.

Read my full tuning eye article published in magazine.

If you liked my article, you will enjoy a visit to This very well put together web site contains a fair amount of unique information about magic eye tubes, and has an excellent section with animated gifs to show eyetube operation.

One interesting use of the EAM86 eye tube in a Korting Radio is described by Hans Knoll at The direct link to the EAM86 post is here.

TUNE-A-LITE tuning indicator used in FADA RW chassis

and the modern version as a Russian IN-9 neon analog bargraph used with a classic AC/DC tube radio for tuning indication.

A transconductance circuit turns the IN-13 neon analog bargraph into a general purpose voltmeter with a 5V input range.

Measurements and experimentation with AGC action and detection in a classic AC/DC tube radio.

Circuit makes simultaneous measurement of Firing voltage and Sustain (on) voltage of neon bulbs, nixies and other gas discharge tubes.

Pinout for Russian NH-33 self scan stereo indicator display from .KWTUBES on ebay

Exotic optical mystery tube from This link gets you to the page with the tube description of a Fairradio part number XTUBE-98 about 3/4 of the way down the page. It sells for $20. I got one of these and took a few pictures. Do you know what it is. The face of the tube looks like an optical surface. What seems like a filament measures about 0.4 Ohms.

A_crystal_that_amplifies_Radio_News_October_1948 This is probably the first ever published transistor construction article. In this case, the article is about building Point contact transistors from 1N34 point contact diodes. The article was published less than a year after Bell Labs anounced their version of the first transistor.

Why triodes, with tank loads, oscillate, unless measures are taken to neutralize the effects of Miller feedback plate-grid capacitance. Frederick E. Terman explains it in three of his books.

Singer TV6 schematic scanned from owner's manual

Singer TV6 zipped file with manual, schematic, and photos 3.7MB


Xophonic Article in Radio TV News June 1957

Electromechanical digital Voltmeter from 1955 with tubes, relays and an incandescent bulb digital display  NLS_519-P_1955_Digital_Voltmeter.PDF

Electromechanical digital Voltmeter from 1959 with tubes, relays, germanium transistors, and an incandescent bulb digital display  NLS_DVM_models_M-24_and_V-24.PDF

Article in Electronics World magazine describing a digital tube voltmeter in 1963  Inside_a_digital_Voltmeter_NLS_1963.pdf


Hollywood Radio and Television Institute radio repair orrespondence course kit radio construction lesson in Portuguese HRTI_10L.pdf 2.5MB 20 pages

samples of the news letter and lesson covers in Spanish and Portuguese HRTI_lessons_news.pdf 2.2MB

Nixie-Xmas-Tree  uses a 1N117 Power beam pentode/rectifier to light up a 1930's choke like a christmas tree.

A web page for old radio enthusiasts can be found at The Forum is open to all for reading. Membership is available for a small fee. Free schematic and picture dowloads are available if you upload schematics or photos of old radios. One schematic upload entitles you to approximatelly 360 dowloads. This is the most formal hobby page on the web I have come across; it has a steep learning curve. The password arrives in a registered letter. The best part is the Forum, where you will find some of the best posts and most competent old radio hobbyists anywhere. The topic coverage is particularly rich in European radio design.

How to invert video in 1995 to look at photgraphic negatives on a video monitor  7.8MB Video_inverter_1995_RE.pdf.

Sears Silvertone Trav-ler 5 tube portable radio restoration. One single tuned circuit at the loop antenna. 2 untuned trasnformer coupled RF stages. Heater voltage control rehostat. Volume control attenuates signal by forward biasing the grid bias of the RF stages, thus shunting out the signal. Hand traced Trav-ler schematic in LTSpice with screen shots and editable and simulatable versions.

Orthicon_RCA_Review_V4-2_1939.pdf (4.8MB)  Now with TEXT: Orthicon_RCA_Review_V4-2_1939 OCR.pdf (1.5MB) An article from the RCA Review Volume 4 number 2, published in 1939, about the original development of the Orthicon image tube. This article contains reference to experimental devices that led to the Orthicon. These devices confer historic context and help explain the many sophisticated techniques embodied in the Orthicon.

RCA_Review_1940-V4_April_Vestigial_Sideband.pdf (4.8MB)Vestigial lower sidband modulation is used universally for Video broadcast. A good treatment of this topic can be found in in this article. April 1940 RCA Review pp425-440 "Selective Sideband Transmission in Television" by R. D. Kell and G.L. Fredendall.

RCA_review_V4-4_April_1940_478-484_OCR.pdf (0.5MB)  The Limits of Inherent Frequency Stability WALTER VAN B. ROBERTS (searcheable text, compressed scan)

RCA_review_V4-4_April_1940_478-484.pdf (1.4MB) The Limits of Inherent Frequency Stability WALTER VAN B. ROBERTS (no text, high resolution scan)

Signalite Glow lamps Gatalog 1979, Neon bulbs, trigger tubes, voltage regulators, Neon indicators. 8.6MB pdf format.

Signalite Articles and notes that came with catalog.

English language translation of Russian data sheet for subminiature filamentary tubes:

VHF Mixing tube 1ZH37B/1J37B (September 2009)

100MHz power pentode 1P24B. (October 2009)

These two data sheets were kindly translated by MIT Electrical Engineering student Dimitri Turbiner.

Thank you Dimitri!

Application note for the 6360 dual Tetrode from Amperex (1.4MB pdf)

Reflex_Radio_Receivers_1924.pdf 8.4MB A small 64 page book about reflex radio receiver designs from 1924. Most of the coverage is schematic oriented. There is section that discusses components, but there is relatively little showing constructions. This book was lent by Terry Walker for scanning and uploading by me, Joe Sousa. Please feel free to share widely. Thank you, Terry for lending the book.

Reflex_Radio_Receivers_1924_OCR.pdf 2.8MB is a more compressed version of the scans, but it includes OCR text that can be searched or translated.

Supplemental files for article: Sputnik - 9V Superheterodyne tube radio .









Jim's World   Jim William's office May 2000.

Service manual for Panoramic Panalyzor SB-8a and Panadapter SA-8a 12.7MB Panoramic Panalyzor Sa-8a SB-8a.pdf

The user manual for the SA-8b is at BAMA.

This pioneering spectrum analyzer instrument was designed in the late 1940's by Ben Tongue at the start of this long career. See an interview of Ben Tounge at the Cable Center.

Repost of book by  "Applications_of_neon_lamps_and_Gas_discharge_tubes-Edward_Bauman " which I found somewhere on the web, but can't remember where.

The following two RCA books have searcheable text, that was added with the FineReader12 OCR program from ABBYY.



The original book image scans without text were obtained from Peter Millett's web site at

The following are scans of various publications that I got for free in October 2015 at the Tube Collectors Association meeting at the Computer History Museum in Mountain View CA. Thanks to whoever perserved these gems.

The Transistor successor to the Vacuum tube - Motorola 1952 OCR.pdf  (0.9MB)

Factors in the design of point-contact transistors Slade RCA 1953 OCR.pdf (0.6MB)

Survey of Transistor development Slade RCA 1952 OCR.pdf (2.4MB)

Ferrite applications in electronic components RCA 1952 OCR.pdf (0.7MB)

6BQ7 new low noise twin triode RCA 1952 OCR.pdf (1.1MB)

Video of Home electronics lab Lawrence June 2016. (240MB mp4, right-click-save to download). Lab has been taken down, simplified and moved to new home. The video is also viewable on thisYouTube link.

Robert J Widlar wrote a course about transistor operation for the US Air Force in 1960 as Airman First Class A1C. The following is quoted from the front page of the 237 page pdf scan












The last six pages of this scan include his resume from 1966.

Bob_Widlar_A1C_LowryAFB-CO_Transistors_1960.pdf 11MB.

This course has no equations, but has excellent rigorous writing with a profusion of illustrations. This makes for a good companion to a more conventionally written book on bipolar Junction transistors, where equations often eclipse the fundametal physics with idealized mathematical approximations.

The paper copy of this course was kindly given to me at Linear Technology by my new colleague Mark Maddox from Analog Devices on the occasion of the merger of Linear Technology and Analog Devices. An extraordinary "company warming" gift!

My SP4010 precision buffer amplifier. I designed this amplifier with a unique architecture in 1987. It was a hybrid design and included my first IC design.