http://www.philbrickarchive.org/1982_Philbrick_4701-4713-4725.pdf is the data sheet of the Teledyne Philbrick 4701 V/F converter.

First part of a series describing how an ASIC can be designed for the https://efabless.com/tinytapeout project, by Andy Turudic.
See also the article https://www.electronicdesign.com/blogs/nonlinearities/article/55134043/electronic-design-sothe-z80-is-rising-from-the-deadwith-an-on-chip-dac

Technique to extend bandwidth invented at Tektronix, found on https://w140.com/tekwiki/wiki/Bridged_T-coil

Includes US patent 2,883,619 Electrical Probe by John R. Kobbe and William J. Polits awarded on April 21, 1959 for use of a resistive center conductor.
The site was found via a link on the Tektronix wiki https://w140.com/tekwiki/wiki/Risetime_Calculator

"Bringing Nixie tubes back to life" - small manufacturer of Nixie tubes and clocks in Březolupy, Czech republic, https://www.openstreetmap.org/search?query=B%C5%99ezolupy#map=13/49.11641/17.61486
Found on Jamie Zawinski's blog https://www.jwz.org/blog/2024/09/cathode-poisoning/, https://www.jwz.org/blog/2024/09/cathode-poisoning/#comment-252180

Found a link to the floppy disc head alignment on the MoHP https://www.hpmuseum.org/forum/thread-22003-post-189057.html#pid189057

This section of the site offers RF engineers quick access to popular calculators and design aids. They are useful at design time and for training purposes, both of which stimulated their development and use over the years. Each tool is written in Javascript and the user can view the page source should they wish to examine the implementation.

I have tried to include references to the various books/papers that I have used in the development of each tool and although I have used them all at various times and believe them to be accurate, please use due diligence and further simulate where necessary.

Most of the tools come with sample values pre-entered into each input box to offer a degree of help. I apologise if this bothers you, but from the feedback I receive, it is generally preferred.

Please be sure to have read the "terms of use". The link is available at the bottom of every page.

Found on https://www.ukraa.com/store/categories/e-field-probe/e-field-active-antenna-masthead-amplifier-and-bias-t
The author claims that the capacitance of a cylindrical plate is proportional to its diameter rather than its area.

An analogue frontend is available on https://store.fhdm.xyz/dso-500k

Badger 2040 is a programmable E Paper/eInk/EPD badge, powered by RP2040. Badger 2040 W is a programmable E Paper/eInk/EPD badge with 2.4GHz wireless connectivity, powered by Raspberry Pi Pico W. Both can go into a deep sleep mode between updates to preserve battery.