Author Topic: Obsolete technologies you never knew existed  (Read 6228 times)

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Offline Analog Kid

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Re: Obsolete technologies you never knew existed
« Reply #100 on: January 12, 2025, 09:58:09 pm »
Christmas tree bulbs, until a ten years ago.
When they went out, the whole bunch would go dark, so I had my dad change them. can't even get the bulbs, so now they're LEDs. :popcorn:

While we're on the topic of incandescent Xmas tree lights, how about those things they used to sell in the last days of those lights (practically nobody uses them any more, although you can still buy replacement bulbs for the larger sizes), that supposedly would "fix" a string of lights that had gone open-circuit? As I remember they used a high-ish voltage pulse through the string to fuse an open bulb short so the string would light again, or something like that.

They actually worked--sometimes. Of course, after that there were fewer working bulbs in series, so the failure rate of the other bulbs would start to escalate.
 

Offline Njk

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Re: Obsolete technologies you never knew existed
« Reply #101 on: January 12, 2025, 11:10:58 pm »
A guy from ST once visited us to deliver a lecture on the VLIW architecture. He had a nice French accent and in the end all the listeners were awarded with an elegant souvenir flashlight that uses incandescent bulb. A special feature is the replacement bulb, which is hidden deeply inside. Its existence can only be known from the user's manual.
 

Online themadhippy

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Re: Obsolete technologies you never knew existed
« Reply #102 on: January 12, 2025, 11:16:51 pm »
Quote
A special feature is the replacement bulb,
is it in the endcap cause i thought that was common knolage
 

Offline Analog Kid

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Re: Obsolete technologies you never knew existed
« Reply #103 on: January 13, 2025, 12:00:07 am »
I knew about those!
My hardware store sold replacement Maglite parts, including those special bulbs with the two wire leads.
Micro-halogens, I believe.
 

Online BrianHG

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Re: Obsolete technologies you never knew existed
« Reply #104 on: January 13, 2025, 01:12:29 am »
A 1950's mechanical relay switched, 6v in, 60hz 120v out inverter

 

Offline Njk

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Re: Obsolete technologies you never knew existed
« Reply #105 on: January 13, 2025, 01:40:48 am »
Micro-halogens, I believe.
You think so? Looks like an ordinary bulb, measures 0.65 Ohm when cold. Some kind of lens on the light emitting end.
 

Online Bud

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Re: Obsolete technologies you never knew existed
« Reply #106 on: January 13, 2025, 01:42:09 am »
Quote
A special feature is the replacement bulb,
is it in the endcap cause i thought that was common knolage
I burned all spares in mine years ago but recently put an LED replacement into it that I got from Ali. It is amazing how much punch can a single AAA keychain pen light deliver. Blows the original incandescent bulb out of water. And gave my Mag a second life.
Facebook-free life and Rigol-free shack.
 

Offline Analog Kid

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Re: Obsolete technologies you never knew existed
« Reply #107 on: January 13, 2025, 01:43:15 am »
I know there are halogen Maglite bulbs, like this one: https://maglite.com/products/replacement-lamp-bulb-for-mag-charger-halogen-flashlight

Not sure about those little itty-bitty ones, though.
 

Online TimFox

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Re: Obsolete technologies you never knew existed
« Reply #108 on: January 13, 2025, 02:34:14 am »
The bright incandescent bulbs in MaglitesTM were often filled with xenon, a heavy inert gas.
https://maglite.com/collections/replacement-lamps/products/replacement-xenon-lamp-bulb-for-mini-maglite-2-cell-aa-aaa-flashlight
 

Offline 5U4GB

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Re: Obsolete technologies you never knew existed
« Reply #109 on: January 13, 2025, 04:20:11 am »
A 1950's mechanical relay switched, 6v in, 60hz 120v out inverter

Isn't that just a vibrator power supply in a hammer-finish case?

As an aside, Silicon Chip magazine (AU) has published a few articles on vibrators recently, including various circuits for solid-state replacements for the original mechanical devices.
« Last Edit: January 13, 2025, 04:23:38 am by 5U4GB »
 

Offline Halcyon

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Re: Obsolete technologies you never knew existed
« Reply #110 on: January 13, 2025, 09:21:50 am »
Quote
A special feature is the replacement bulb,
is it in the endcap cause i thought that was common knolage

Maglites came with a spare bulb in the end-cap wrapped in foam. It was featured in the manuals from the double-cell AA upwards.
 

Online themadhippy

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Re: Obsolete technologies you never knew existed
« Reply #111 on: January 13, 2025, 11:16:46 am »
Quote
with a spare bulb in the end-cap wrapped in foam
no foam on my mini,it has a plastic insert to hold the spare.
 

Offline valcher

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Re: Obsolete technologies you never knew existed
« Reply #112 on: January 13, 2025, 12:13:15 pm »
In the past glow discharge lamps were widely used as reference voltage sources, it would be interesting to compare them with modern semiconductor zener diodes. Has anyone had experience using them?
 

Online Zero999

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Re: Obsolete technologies you never knew existed
« Reply #113 on: January 13, 2025, 12:26:59 pm »
Unless one has seen the inside of a 1950s-era automobile radio, the vibrator power supply comes to mind.
Seen that in my father's car. A devices like that were sometimes called umformers. Produced a hum sound, similar to a cooling fan. BTW the old loudspeakers also produced some hum because there were no permanent magnets. Instead, the magnetic field was created by passing a (usually poorly smoothed) DC through a dedicated winding in the base part. The hum was quite annoying.
Was no attempt made at cancelling the hum? It should be easy to do either inside the amplifier or by an auxilary winding on the virbrator coil into the speaker field.
 

Online tggzzz

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Re: Obsolete technologies you never knew existed
« Reply #114 on: January 13, 2025, 06:23:05 pm »
In the past glow discharge lamps were widely used as reference voltage sources, it would be interesting to compare them with modern semiconductor zener diodes. Has anyone had experience using them?

I've had a Solartron LM1420 voltmeter, but I have now sold it so I can't do any serious tests.

It used a neon as the secondary reference, with an internal unsaturated Weston standard cell (still in spec, unexpectedly) as the primary reference. My characterisation based on playing around a little bit: the neon voltage was unpredictable, but once the reading was adjusted against the Weston it was stable enough for a 3.5 digit DVM. By that I mean after a week being turned off in a domestic environment, the reading did not need re-adjustment.
There are lies, damned lies, statistics - and ADC/DAC specs.
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Offline valcher

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Re: Obsolete technologies you never knew existed
« Reply #115 on: January 13, 2025, 07:09:45 pm »
I have almost never had any experience with tube measuring equipment, but recently I read that the gas tube reference is superior in noise and temperature stability to semiconductor zener diodes.
https://jacmusic.com/Sovtek/index.html (at the end of the article)
 

Offline Xena E

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Re: Obsolete technologies you never knew existed
« Reply #116 on: January 13, 2025, 07:52:15 pm »
Unless one has seen the inside of a 1950s-era automobile radio, the vibrator power supply comes to mind.
Seen that in my father's car. A devices like that were sometimes called umformers. Produced a hum sound, similar to a cooling fan. BTW the old loudspeakers also produced some hum because there were no permanent magnets. Instead, the magnetic field was created by passing a (usually poorly smoothed) DC through a dedicated winding in the base part. The hum was quite annoying.
Was no attempt made at cancelling the hum? It should be easy to do either inside the amplifier or by an auxilary winding on the virbrator coil into the speaker field.

The output transformers of valve audio equipment that had single ended audio output stages were sometimes given a hum bucking winding, basically a tap that powered the rest of the equipment to cancel the ripple induced hum.
 

Offline Njk

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Re: Obsolete technologies you never knew existed
« Reply #117 on: January 15, 2025, 04:08:42 pm »
Awesome teapot, the nuts and wire in the loop look especially cool  :-+
It's not a wire, it's an old bicycle spoke
 

Offline Njk

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Re: Obsolete technologies you never knew existed
« Reply #118 on: January 15, 2025, 04:12:12 pm »
A 1950's mechanical relay switched, 6v in, 60hz 120v out inverter
It's already mentioned here. The thing for car radio is not a motor-generator, it's more like a vibration pump in a cheap coffee machine
 

Offline Njk

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Re: Obsolete technologies you never knew existed
« Reply #119 on: January 15, 2025, 04:56:48 pm »
I burned all spares in mine years ago but recently put an LED replacement into it that I got from Ali. It is amazing how much punch can a single AAA keychain pen light deliver. Blows the original incandescent bulb out of water. And gave my Mag a second life.
Seen the pictures and mixed reviews. Seems the thick heatsink disk prevents the reflector end from being fully screwed to the main body part, resulting in poor beam regulation. That's all about using LEDs in such applications. More light but in dumb way. No one cares about beam forming any more. I's bright so it's easy to sell. I would prefer another approach. Keep the old bulb's light amount (call it a gold standard) but improve the beam by better optics and consume less power from the battery to extend the run time. But it's not popular.
 

Offline Xena E

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Re: Obsolete technologies you never knew existed
« Reply #120 on: January 15, 2025, 05:00:19 pm »
A 1950's mechanical relay switched, 6v in, 60hz 120v out inverter
It's already mentioned here. The thing for car radio is not a motor-generator, it's more like a vibration pump in a cheap coffee machine

Fundamental Principles of Vibrator Power Supply Design. Mallory (PDF) 13Mb

https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=http://www.tubebooks.org/books/intro_mallory_vibe.pdf&ved=2ahUKEwiV_v3Nl_iKAxWJQUEAHSmtO4EQFnoECBIQAQ&usg=AOvVaw3SwCzbfZEpW9D1TnwaoZZK
 

Offline Njk

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Re: Obsolete technologies you never knew existed
« Reply #121 on: January 15, 2025, 05:07:19 pm »
Was no attempt made at cancelling the hum? It should be easy to do either inside the amplifier or by an auxilary winding on the virbrator coil into the speaker field.
With a high quality DC the hum is just not there. BTW a permanent magnet can be not so permanent in fact. Those who're restoring old loudspeakers knows that. An old weak magnet can be charged with more magnetism by placing it in the center of improvised winding and using a DC welding machine to pass strong current pulse through the winding
 

Offline Njk

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Re: Obsolete technologies you never knew existed
« Reply #122 on: January 15, 2025, 05:54:03 pm »
I've had a Solartron LM1420 voltmeter, but I have now sold it so I can't do any serious tests.

It used a neon as the secondary reference, with an internal unsaturated Weston standard cell (still in spec, unexpectedly) as the primary reference. My characterisation based on playing around a little bit: the neon voltage was unpredictable, but once the reading was adjusted against the Weston it was stable enough for a 3.5 digit DVM. By that I mean after a week being turned off in a domestic environment, the reading did not need re-adjustment.
I had a pulse generator equipped with neon bulb. There were two knobs for pulse amplitude setting, one knob with the scale and the other one for actual amplitude control. User have to set desired amplitude with the first knob and rotate the second knob till the neon bulb became lit (sort of comparator)
« Last Edit: January 15, 2025, 05:57:16 pm by Njk »
 

Online schmitt trigger

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Re: Obsolete technologies you never knew existed
« Reply #123 on: January 15, 2025, 11:24:03 pm »
Love the URSS-era electronic equipment.
 


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