UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > General Vintage Technology > General Vintage Technology Discussions

Notices

General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc.

Reply
 
Thread Tools
Old 26th Sep 2019, 10:12 am   #61
Jon_G4MDC
Heptode
 
Jon_G4MDC's Avatar
 
Join Date: Nov 2015
Location: Welwyn Garden City, Hertfordshire, UK.
Posts: 710
Default Re: Your first experience with LEDs?

I think the sales boom for LED watches was more due to Kojak.
Not many could afford the Omega one!
Jon_G4MDC is online now   Reply With Quote
Old 9th Oct 2019, 6:37 pm   #62
Steve G4WCS
Hexode
 
Steve G4WCS's Avatar
 
Join Date: Sep 2004
Location: Preston, Lancashire, UK.
Posts: 261
Default Re: Your first experience with LEDs?

Some early tri colour leds, a cds photocell, and a couple of nice military standard panel indicators, on with an nve filter
Attached Thumbnails
Click image for larger version

Name:	2C12D15C-DC29-45FF-A279-8197FDA35EE4.jpg
Views:	54
Size:	100.5 KB
ID:	191579   Click image for larger version

Name:	408E3105-2D31-43F8-8287-F4F0167EF968.jpg
Views:	55
Size:	57.6 KB
ID:	191580  
Steve G4WCS is offline   Reply With Quote
Old 9th Oct 2019, 6:41 pm   #63
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 7,783
Default Re: Your first experience with LEDs?

I remember those DIL-packaged sets-of-LEDs - I built a battery-condition indicator for one of my cars using one of those and a chip - LM39something - that was specifically designed as a driver for such applications - there were 2 versions, one log, the other linear; the log ones were invariably used as level/drive-indicators in recording applications and transmitter modulators.
G6Tanuki is offline   Reply With Quote
Old 9th Oct 2019, 6:48 pm   #64
Steve G4WCS
Hexode
 
Steve G4WCS's Avatar
 
Join Date: Sep 2004
Location: Preston, Lancashire, UK.
Posts: 261
Default Re: Your first experience with LEDs?

Quote:
Originally Posted by G6Tanuki View Post
I remember those DIL-packaged sets-of-LEDs - I built a battery-condition indicator for one of my cars using one of those and a chip - LM39something - that was specifically designed as a driver for such applications - there were 2 versions, one log, the other linear; the log ones were invariably used as level/drive-indicators in recording applications and transmitter modulators.
LM3914 linear, 3915 log, up to 10 could be cascaded, they were fun
Steve G4WCS is offline   Reply With Quote
Old 9th Oct 2019, 6:51 pm   #65
Steve G4WCS
Hexode
 
Steve G4WCS's Avatar
 
Join Date: Sep 2004
Location: Preston, Lancashire, UK.
Posts: 261
Default Re: Your first experience with LEDs?

The chinese are all over them
Attached Thumbnails
Click image for larger version

Name:	732683AF-F4F5-45EE-A73E-27E3FB62DFE8.jpg
Views:	59
Size:	36.8 KB
ID:	191584  
Steve G4WCS is offline   Reply With Quote
Old 9th Oct 2019, 6:53 pm   #66
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 7,783
Default Re: Your first experience with LEDs?

Quote:
Originally Posted by Steve G4WCS View Post
LM3914 linear, 3915 log, up to 10 could be cascaded, they were fun
Yes that's the beasties. They were rather nifty when compared with the effort needed to achieve the same result with discrete transistors and a voltage-divider network.

I remember that you could even at one time buy those DIL "Bar-graph" LEDs which had the first 6 or 7 LEDs green, then a couple of orange and finally one red, specifically for use with the 3914/3915 chips.
G6Tanuki is offline   Reply With Quote
Old 9th Oct 2019, 7:12 pm   #67
Steve G4WCS
Hexode
 
Steve G4WCS's Avatar
 
Join Date: Sep 2004
Location: Preston, Lancashire, UK.
Posts: 261
Default Re: Your first experience with LEDs?

Definitely, we had test sets with lm311 comparator and resistor chains to do a similar thing
Steve G4WCS is offline   Reply With Quote
Old 10th Oct 2019, 4:46 am   #68
TonyDuell
Dekatron
 
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 3,356
Default Re: Your first experience with LEDs?

Wasn't there also an LM3916, which was a similar bargraph driver with yet another response curve?

You could also get at one time little PCBs with the LED and LM3914 dice directly on the board and bonded out to each other. A dozen or so external connections to the LM3914 connections other than most of those for the LEDs. RS did them, I still have the datasheet. I have one used as a battery condition indicator in a piece of telecoms test equipment (Tester 301B), one of the LEDs or its connection has failed alas. It's not important (it's used in bar rather than dot mode, so the missing LED simply appears as a gap in the bar and I can still tell when the battery needs charging) but I'd like to replace it. But finding a replacement is hard, it pretty much has to be the original module to fit in the space.
TonyDuell is offline   Reply With Quote
Old 10th Oct 2019, 6:31 am   #69
julie_m
Dekatron
 
Join Date: May 2008
Location: Derby, UK.
Posts: 7,383
Default Re: Your first experience with LEDs?

I've seen cassette decks where one bargraph driver IC was multiplexed to drive two rows of LEDs alternately.

The design confused me at first, because there did not seem to be an oscillator controlling the switching, nor any transistors that looked good for the full current .....
__________________
If I have seen further than others, it is because I was standing on a pile of failed experiments.
julie_m is offline   Reply With Quote
Old 10th Oct 2019, 8:31 am   #70
mark2collection
Hexode
 
mark2collection's Avatar
 
Join Date: Jul 2010
Location: Royal Berkshire, UK.
Posts: 325
Default Re: Your first experience with LEDs?

I built a power amp a good few years back using a pair of LM39** to drive a couple of bar graphs as VU meters.

Cross-linking the cathode from LED 1 to anode of LED 2 and so on, up the chain gave a wonderful fade effect, where the upper-most LED would be dim, the next one down, slightly brighter and the 1st LED nice and bright, for example.

At full tilt with a hearty beat the effect was obvious, too loud and the whole bar graph would flash.

Mark
__________________
Slowly turning the 'to-do', into 'ta-dah'
mark2collection is offline   Reply With Quote
Old 11th Oct 2019, 2:49 pm   #71
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 7,783
Default Re: Your first experience with LEDs?

Quote:
Originally Posted by TonyDuell View Post
Wasn't there also an LM3916, which was a similar bargraph driver with yet another response curve?
Yes the 3914 was a linear display, the 3915 a +3dB increment display and the 3916 was a VU-meter [with different increments at the bottom and top end of its range]

Quote:
Originally Posted by TonyDuell View Post
You could also get at one time little PCBs with the LED and LM3914 dice directly on the board and bonded out to each other. A dozen or so external connections to the LM3914 connections other than most of those for the LEDs. RS did them, I still have the datasheet. I have one used as a battery condition indicator in a piece of telecoms test equipment (Tester 301B), one of the LEDs or its connection has failed alas. It's not important (it's used in bar rather than dot mode, so the missing LED simply appears as a gap in the bar and I can still tell when the battery needs charging) but I'd like to replace it. But finding a replacement is hard, it pretty much has to be the original module to fit in the space.
Yes, that was the NatSemi NSM391xx-series; the chip being bonded direct to the PCB and covered with a lump of black or brown epoxy. The same bond/encapsulate technology was common in 'integrated' applications back then, a lot of the cheap 4-digit LED clocks/clock-radios used it. In theory it was more reliable than a conventionally-encapsulated chip soldered to a PCB, but I've found this not to be the case!
G6Tanuki is offline   Reply With Quote
Old 24th Oct 2019, 9:41 pm   #72
avocollector
Hexode
 
Join Date: Jul 2010
Location: Wellington, New Zealand.
Posts: 432
Default Re: Your first experience with LEDs?

My first LED was in a watch of which I was mightily proud as it seemed to futuristic. One point about car/bike ignition systsm is I have allways wondered why they do not use some variant of the pizeo electric ignition buttons as on gas torches or barbecues. Surely some sort of drive off the car timing belt and cam operating a pizeo button could achieve the spark with using a battery or electronics (save for the pizeo circuit) at all.
avocollector is offline   Reply With Quote
Old 24th Oct 2019, 10:48 pm   #73
broadgage
Octode
 
Join Date: Jan 2010
Location: North Somerset, UK.
Posts: 1,369
Default Re: Your first experience with LEDs?

Quote:
Originally Posted by avocollector View Post
My first LED was in a watch of which I was mightily proud as it seemed to futuristic. One point about car/bike ignition systsm is I have allways wondered why they do not use some variant of the pizeo electric ignition buttons as on gas torches or barbecues. Surely some sort of drive off the car timing belt and cam operating a pizeo button could achieve the spark with using a battery or electronics (save for the pizeo circuit) at all.
I asked the question decades ago and was told that piezo crystals were not sufficiently durable. They are fine for lighting a gas flame, but even at a few times a day in an appliance that lasts 10 years, that is only 10,000 operations.
For ignition in an engine, many millions of operations would be needed rather than a few thousand.
broadgage is online now   Reply With Quote
Old 24th Oct 2019, 11:07 pm   #74
Gonzini
Pentode
 
Gonzini's Avatar
 
Join Date: Dec 2006
Location: Wickham, Hampshire, UK.
Posts: 107
Default Re: Your first experience with LEDs?

Think I'm going to have to dig out the vintage LED collection, it's been while since I last looked.
Gonzini is offline   Reply With Quote
Old 27th Oct 2019, 3:10 pm   #75
adriang
Diode
 
Join Date: Nov 2016
Location: Bedfordshire, UK.
Posts: 2
Default Re: Your first experience with LEDs?

First one was a 3mm red in the '70's sometime, from RS. It was used in a logic probe - a design from one of the magazines that used a 7400 as a flipflop to extend the pulse.

Later I got some of those claw-shaped monsanto 7-seg displays referred to earlier with the intention of making a DVM (never completed, though I may still have the display board).
adriang is offline   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 1:56 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Copyright ©2002 - 2019, Paul Stenning.