# \#electronics **URL:** https://scanalyst.fourmilab.ch/tag/electronics/872.md [Latest](https://scanalyst.fourmilab.ch/latest.md) · [Categories](https://scanalyst.fourmilab.ch/categories.md) · [Tags](https://scanalyst.fourmilab.ch/tags.md) --- ## [Netherlands takes over chip manufacturer Nexperia](https://scanalyst.fourmilab.ch/t/netherlands-takes-over-chip-manufacturer-nexperia/6127)
**Author:** [@eggspurt](https://scanalyst.fourmilab.ch/u/eggspurt)\ **Replies:** 0\ **Last updated:** [13 October 2025 16:13 UTC](https://scanalyst.fourmilab.ch/t/netherlands-takes-over-chip-manufacturer-nexperia/6127 "2025-10-13T16:13:28Z")
Europe is finally beginning to challenge China. Dutch government took over the company with a Chinese CEO under a law that ensures availability of the products & technology in an emergency, perhaps as a response to the … --- ## [Straws in the International Wind(s)](https://scanalyst.fourmilab.ch/t/straws-in-the-international-wind-s/4861)
**Author:** [@Gavin](https://scanalyst.fourmilab.ch/u/Gavin)\ **Replies:** 0\ **Last updated:** [26 August 2024 15:21 UTC](https://scanalyst.fourmilab.ch/t/straws-in-the-international-wind-s/4861 "2024-08-26T15:21:06Z")
Here’s another happening that the LameStream Media seem to have missed: US tech giant disbands research division in China – media — RT Business News "International Business Machines Corporation (IBM) is closing its res… --- ## [History of the Alternating Current Transformer](https://scanalyst.fourmilab.ch/t/history-of-the-alternating-current-transformer/3587)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 1\ **Last updated:** [24 January 2024 22:10 UTC](https://scanalyst.fourmilab.ch/t/history-of-the-alternating-current-transformer/3587 "2024-01-24T22:10:37Z")
No, despite his claims later in life and their being repeated by gullible journalists and biographers, Nikola Tesla had nothing to do with the invention of the AC transformer. His Tesla coil was a resonant… --- ## [Understanding Electronic Circuits with Gears and Chains](https://scanalyst.fourmilab.ch/t/understanding-electronic-circuits-with-gears-and-chains/4235)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 7\ **Last updated:** [20 January 2024 20:37 UTC](https://scanalyst.fourmilab.ch/t/understanding-electronic-circuits-with-gears-and-chains/4235 "2024-01-20T20:37:14Z")
Spintronics, from Upper Story, is an educational building block set which allows construction of mechanical analogues to electrical circuits in which chains serve as wires and cleverly designed components a… --- ## [World's Smallest Round Cathode Ray Tube Video Display](https://scanalyst.fourmilab.ch/t/worlds-smallest-round-cathode-ray-tube-video-display/4181)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [5 January 2024 16:28 UTC](https://scanalyst.fourmilab.ch/t/worlds-smallest-round-cathode-ray-tube-video-display/4181 "2024-01-05T16:28:08Z")
Before the advent of liquid crystal video displays, some video camera/recorders (camcorders) used tiny cathode ray tubes to provide a viewfinder that monitored the actual video produced by the image sensor.… --- ## [Powering Up a 1950s Bendix G-15 Vacuum Tube Computer](https://scanalyst.fourmilab.ch/t/powering-up-a-1950s-bendix-g-15-vacuum-tube-computer/4146)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [28 December 2023 14:09 UTC](https://scanalyst.fourmilab.ch/t/powering-up-a-1950s-bendix-g-15-vacuum-tube-computer/4146 "2023-12-28T14:09:41Z")
When you have a half tonne computer containing 450 vacuum tubes and a magnetic drum memory spun at 1800 RPM by a big AC induction motor, just turning on the power is an exciting event. The Bendix G-15, int… --- ## [How Do Series String Christmas Lights Keep Working When One Burns Out?](https://scanalyst.fourmilab.ch/t/how-do-series-string-christmas-lights-keep-working-when-one-burns-out/4127)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [22 December 2023 16:09 UTC](https://scanalyst.fourmilab.ch/t/how-do-series-string-christmas-lights-keep-working-when-one-burns-out/4127 "2023-12-22T16:09:06Z")
Wiring Christmas tree lights in series saves money, as only one wire runs between bulbs, and also reduces clutter compared to parallel connection which would require two wires. But, with a series connectio… --- ## [Repairing a 1970s Teletype Tester](https://scanalyst.fourmilab.ch/t/repairing-a-1970s-teletype-tester/4110)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [17 December 2023 14:10 UTC](https://scanalyst.fourmilab.ch/t/repairing-a-1970s-teletype-tester/4110 "2023-12-17T14:10:37Z")
You’ve just spent hours putting everything back together after going through page after page fixing an electromechanical teletype machine. How do you know if you’ve got it right? Well, you could just hook… --- ## [Aligning an 8 Inch Floppy Disc Drive](https://scanalyst.fourmilab.ch/t/aligning-an-8-inch-floppy-disc-drive/3851)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [11 October 2023 11:58 UTC](https://scanalyst.fourmilab.ch/t/aligning-an-8-inch-floppy-disc-drive/3851 "2023-10-11T11:58:47Z")
Earlier posts in the series explored the original 8 inch floppy disc (or diskette) technology and repaired some vintage drives. The Curious World of the 8 Inch Floppy Disc Repairing a Vintage 8 Inch Flopp… --- ## [Inside the Bendix G-15's Magnetic Drum Memory](https://scanalyst.fourmilab.ch/t/inside-the-bendix-g-15s-magnetic-drum-memory/3793)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [26 September 2023 13:24 UTC](https://scanalyst.fourmilab.ch/t/inside-the-bendix-g-15s-magnetic-drum-memory/3793 "2023-09-26T13:24:01Z")
The Bendix G-15 vacuum tube computer used a rotating magnetic drum for its main memory. Except for a few registers internal to the processor, all system memory was kept on the drum, as described in the 202… --- ## [Repairing a Hewlett-Packard 5245L Frequency Counter, Part 7—Plug-in-Palooza and the 18 Gigahertz Summit](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-7-plug-in-palooza-and-the-18-gigahertz-summit/3787)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [25 September 2023 14:34 UTC](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-7-plug-in-palooza-and-the-18-gigahertz-summit/3787 "2023-09-25T14:34:43Z")
The Hewlett-Packard 5245L frequency counter achieved its peak performance in 1968 with the release of the model 5257A Transfer Oscillator, which allowed the frequency counter to measure signals from DC to … --- ## [An Excellent Surge Protector and Junk from eBay](https://scanalyst.fourmilab.ch/t/an-excellent-surge-protector-and-junk-from-ebay/3751)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [16 September 2023 16:15 UTC](https://scanalyst.fourmilab.ch/t/an-excellent-surge-protector-and-junk-from-ebay/3751 "2023-09-16T16:15:41Z")
There are few categories of electrical products as scammy as “surge protectors”. At the Las Vegas Fall COMDEX show in 1982 where we introduced AutoCAD, it seemed like every fourth or fifth booth was somebody of whom you… --- ## [Origin of the Cavity Magnetron](https://scanalyst.fourmilab.ch/t/origin-of-the-cavity-magnetron/3669)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [29 August 2023 12:21 UTC](https://scanalyst.fourmilab.ch/t/origin-of-the-cavity-magnetron/3669 "2023-08-29T12:21:09Z")
Here is more about the cavity magnetron. Curiously, the first magnetron (not yet using a cavity resonator) was invented by Albert W. Hull of the General Electric Research Laboratory in the early 1920s as a… --- ## [Street Light Day/Night Sensors](https://scanalyst.fourmilab.ch/t/street-light-day-night-sensors/3662)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [27 August 2023 14:23 UTC](https://scanalyst.fourmilab.ch/t/street-light-day-night-sensors/3662 "2023-08-27T14:23:50Z")
It’s more subtle than you might think. How do you keep the light from blinking off and on around dawn and dusk when light is near the threshold and variable? What about snow accumulating on the sensor in … --- ## [Magnetic Drum Memory from a 1950s Bendix G-15 Vacuum Tube Computer](https://scanalyst.fourmilab.ch/t/magnetic-drum-memory-from-a-1950s-bendix-g-15-vacuum-tube-computer/3637)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [21 August 2023 12:33 UTC](https://scanalyst.fourmilab.ch/t/magnetic-drum-memory-from-a-1950s-bendix-g-15-vacuum-tube-computer/3637 "2023-08-21T12:33:16Z")
Even in the era of vacuum tube computers, where every flip-flop required two vacuum tube components (sometimes in the same envelope), memory was tough. Providing sufficient high-speed (by the standards of … --- ## [Repairing a Hewlett-Packard 5245L Frequency Counter, Part 6—Twelve Gigahertz and the Technician from Hell](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-6-twelve-gigahertz-and-the-technician-from-hell/3612)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [16 August 2023 12:39 UTC](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-6-twelve-gigahertz-and-the-technician-from-hell/3612 "2023-08-16T12:39:11Z")
When you’re confronted with a piece of vintage electronics you’ve picked up at a bargain price at a flea market or auction site, found it totally dead on arrival, and opened it up for a first peek inside, o… --- ## [Converting a 1970s Portable Television into a Composite Video Monitor](https://scanalyst.fourmilab.ch/t/converting-a-1970s-portable-television-into-a-composite-video-monitor/3568)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 1\ **Last updated:** [7 August 2023 13:30 UTC](https://scanalyst.fourmilab.ch/t/converting-a-1970s-portable-television-into-a-composite-video-monitor/3568 "2023-08-07T13:30:52Z")
If you know the input signal is monochrome, removing the filter that takes out the colour signal improves horizontal resolution, but when displaying a signal with chroma information, it’s required to avoid … --- ## [Repairing a Hewlett-Packard 5245L Frequency Counter, Part 5—Dead Out of the Box](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-5-dead-out-of-the-box/3503)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [25 July 2023 11:05 UTC](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-5-dead-out-of-the-box/3503 "2023-07-25T11:05:58Z")
Now that the base 5245L frequency counter is working, the next objective is to collect all of the plug-ins released over the years to extend its functionality. This time, it’s the turn of 5261A video ampli… --- ## [Inside a 1950s Vacuum Tube Computer: Bendix G-15](https://scanalyst.fourmilab.ch/t/inside-a-1950s-vacuum-tube-computer-bendix-g-15/3499)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [24 July 2023 12:11 UTC](https://scanalyst.fourmilab.ch/t/inside-a-1950s-vacuum-tube-computer-bendix-g-15/3499 "2023-07-24T12:11:21Z")
Restoration of the Bendix G-15 vacuum tube computer with magnetic drum memory begins by removing all of the circuit boards, removing the dust and grime of the ages, inspecting each for the usual problems of… --- ## [Repairing a Hewlett-Packard 5245L Frequency Counter, Part 4—Onward to 3 GHz](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-4-onward-to-3-ghz/3483)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [21 July 2023 13:59 UTC](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-4-onward-to-3-ghz/3483 "2023-07-21T13:59:49Z")
The Hewlett-Packard 5245L digital frequency counter, when introduced in 1963, handled a top frequency of 50 MHz, but it had a plug-in slot to accommodate the future. Only a year later, along came the 5254A… --- ## [Don Lancaster, 1940?–2023, R.I.P](https://scanalyst.fourmilab.ch/t/don-lancaster-1940-2023-r-i-p/3398)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 3\ **Last updated:** [3 July 2023 14:15 UTC](https://scanalyst.fourmilab.ch/t/don-lancaster-1940-2023-r-i-p/3398 "2023-07-03T14:15:35Z")
On 2023-06-07, the electronics hobbyist and entrepreneurship communites lost one of its founding fathers with the death of Don Lancaster at the age of 83. Don was truly a microcomputer pioneer and held … --- ## [A 1920s Ozone Generator—“Sea Air in the Home”](https://scanalyst.fourmilab.ch/t/a-1920s-ozone-generator-sea-air-in-the-home/3354)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [23 June 2023 16:15 UTC](https://scanalyst.fourmilab.ch/t/a-1920s-ozone-generator-sea-air-in-the-home/3354 "2023-06-23T16:15:49Z")
Just £9-9-0 in 1925, or around £450 today. Its interrupter high-voltage generator works on either AC mains (“electric light”) current or DC “wireless accumulator” (radio battery bank) power, and a switch s… --- ## [Repairing a Hewlett-Packard 5245L Frequency Counter, Part 3—500 MHz Radio Frequency Magic](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-3-500-mhz-radio-frequency-magic/3307)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [13 June 2023 13:40 UTC](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-3-500-mhz-radio-frequency-magic/3307 "2023-06-13T13:40:01Z")
The Hewlett-Packard engineers who designed the 5245L digital frequency counter in the 1960s weren’t satisfied with its being limited to a top frequency of 50 MHz. How about a plug-in that handles ten times … --- ## [The Birth of Electronics—from the Incandescent Lamp to Digital Logic](https://scanalyst.fourmilab.ch/t/the-birth-of-electronics-from-the-incandescent-lamp-to-digital-logic/3175)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 5\ **Last updated:** [4 June 2023 00:24 UTC](https://scanalyst.fourmilab.ch/t/the-birth-of-electronics-from-the-incandescent-lamp-to-digital-logic/3175 "2023-06-04T00:24:16Z")
The first digital logic gate built from vacuum tubes appears to have been invented by Bruno Rossi in 1930. Rossi, an Italian physicist studying cosmic rays and radioactivity, was not working on computing e… --- ## [Repairing a Hewlett-Packard 5245L Frequency Counter, Part 2](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-2/3189)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [18 May 2023 12:55 UTC](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-2/3189 "2023-05-18T12:55:39Z")
Usually, when a vintage transistor fails, you can replace it with a modern transistor with the same or better specifications (maximum frequency, breakdown voltage, current capacity, etc.), but when you’re d… --- ## [Repairing a Hewlett-Packard 5245L Frequency Counter, Part 1](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-1/3159)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [12 May 2023 12:50 UTC](https://scanalyst.fourmilab.ch/t/repairing-a-hewlett-packard-5245l-frequency-counter-part-1/3159 "2023-05-12T12:50:24Z")
Before the advent of digital electronics, accurately measuring frequency was very difficult. You might ask why this was. All you need to do is accurately measure an interval of time, then count how many o… --- ## [Fixing More 8 Inch Floppy Drives—The Many Forms of Failure](https://scanalyst.fourmilab.ch/t/fixing-more-8-inch-floppy-drives-the-many-forms-of-failure/3078)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [22 April 2023 13:52 UTC](https://scanalyst.fourmilab.ch/t/fixing-more-8-inch-floppy-drives-the-many-forms-of-failure/3078 "2023-04-22T13:52:44Z")
Sometimes you just have to “use one for parts”. --- ## [Repairing a Vintage 8 Inch Floppy Disc Drive](https://scanalyst.fourmilab.ch/t/repairing-a-vintage-8-inch-floppy-disc-drive/3040)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [14 April 2023 11:55 UTC](https://scanalyst.fourmilab.ch/t/repairing-a-vintage-8-inch-floppy-disc-drive/3040 "2023-04-14T11:55:23Z")
The circuit that selects which read head is fed to the signal amplifier is sublimely clever (explanation starts at 9:38 in the video). You’d never do it that way today, but analogue switch ICs did not exis… --- ## [Insanely Complicated “Unstuck in Time” Seven Segment Display](https://scanalyst.fourmilab.ch/t/insanely-complicated-unstuck-in-time-seven-segment-display/2859)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [9 March 2023 14:01 UTC](https://scanalyst.fourmilab.ch/t/insanely-complicated-unstuck-in-time-seven-segment-display/2859 "2023-03-09T14:01:00Z")
This is one of those electronic components that leaves you wondering “What were they thinking?” Functionally, it is a seven segment display, which shows the digits from 0 to 9 and an optional decimal point… --- ## [Radio Telemetry from Inside an Implosion Detonation](https://scanalyst.fourmilab.ch/t/radio-telemetry-from-inside-an-implosion-detonation/2541)
**Author:** [@johnwalker](https://scanalyst.fourmilab.ch/u/johnwalker)\ **Replies:** 0\ **Last updated:** [1 January 2023 14:54 UTC](https://scanalyst.fourmilab.ch/t/radio-telemetry-from-inside-an-implosion-detonation/2541 "2023-01-01T14:54:13Z")
How can you be sure the high explosive implosion system of a nuclear warhead will work after sitting in a silo for years and then being lobbed toward its target by an intercontinental ballistic missile? We… [Next page](https://scanalyst.fourmilab.ch/tag/electronics/872.md?match_all_tags=true&page=1&tags%5B%5D=electronics)