New project on HHH http://sm0vpo.altervista.org/ (www.sm0vpo.com later)
2 posters
Page 1 of 1
Re: New project on HHH http://sm0vpo.altervista.org/ (www.sm0vpo.com later)
Hi Ivan, Yes! yes! YES!!!
I remember the old telephone "baretta" lamp used in telephone exchanges. PYE Telecom used them in the 600 Ohms line controllers for remote radios. They were really common, but today you never hear of them
I remember the story of a Boston telephone engineer who tried impress a telephone operator, around 1920, or so. He strung a few of them in series, plugged them into the wall socket, and the first christmas-tree lights were born.
... and the more recent 28V 50mA telephone lamp https://uk.rs-online.com/web/p/filament-indicator-lamps/2945191/
As you say, the modern replacement LED lamps are not at all suitable.
But my project uses just those bicycle rear lamps you mentioned. They have a small enough mass to allow temperature changes.
Very best regards from Harry
I remember the old telephone "baretta" lamp used in telephone exchanges. PYE Telecom used them in the 600 Ohms line controllers for remote radios. They were really common, but today you never hear of them
I remember the story of a Boston telephone engineer who tried impress a telephone operator, around 1920, or so. He strung a few of them in series, plugged them into the wall socket, and the first christmas-tree lights were born.
... and the more recent 28V 50mA telephone lamp https://uk.rs-online.com/web/p/filament-indicator-lamps/2945191/
As you say, the modern replacement LED lamps are not at all suitable.
But my project uses just those bicycle rear lamps you mentioned. They have a small enough mass to allow temperature changes.
Very best regards from Harry
_________________
Everything in this world is either bacon, or it isn't bacon
They say that money cannot bring you happiness, but if you have it then you can always buy more bacon
Re: New project on HHH http://sm0vpo.altervista.org/ (www.sm0vpo.com later)
Hi Harry,
a tungsten filament lamp has certainly has much less persistence, but it breaks more easily than a thermistor. It may be hard to get now too. I remember two sources of suitable lamps, both are obsolete now: "telephone lamps" used in status lights of phone exchanges and E10 lamps for rear bicycle lights (6V 50mA). LEDs are used on these positions now.
VBR from Ivan
a tungsten filament lamp has certainly has much less persistence, but it breaks more easily than a thermistor. It may be hard to get now too. I remember two sources of suitable lamps, both are obsolete now: "telephone lamps" used in status lights of phone exchanges and E10 lamps for rear bicycle lights (6V 50mA). LEDs are used on these positions now.
VBR from Ivan
Ivan- Posts : 792
Join date : 2012-11-25
Age : 64
Location : Praha, Czechia
Re: New project on HHH http://sm0vpo.altervista.org/ (www.sm0vpo.com later)
Hi Ivan,
Thank you very much for the info. When I made the original design (30 years ago) I tried several thermistors.
The 10mW in the glass envelope work great, but when you change frequency, the output level varies up and down, then settles in about 3 seconds to a constant level. I used a 6v 40mA lamp (from my Philips EE kit) and the lamp stabilised the temperature a lot faster. I tried a carbon-block thermistor (like the one in my 10W HF Linear Amp) and that took up to a 30 seconds to stabilize, but that one used discreet transistors.
For general lab use it should be ok, and will make a useful test tool, but one should be aware of the limitations. I shall buy a pack of those from the link you gave and give them a try, then add the results to the article when I photograph the built prototype.
Thank you once more for the info. Much appreciated.
VBR Harry
Thank you very much for the info. When I made the original design (30 years ago) I tried several thermistors.
The 10mW in the glass envelope work great, but when you change frequency, the output level varies up and down, then settles in about 3 seconds to a constant level. I used a 6v 40mA lamp (from my Philips EE kit) and the lamp stabilised the temperature a lot faster. I tried a carbon-block thermistor (like the one in my 10W HF Linear Amp) and that took up to a 30 seconds to stabilize, but that one used discreet transistors.
For general lab use it should be ok, and will make a useful test tool, but one should be aware of the limitations. I shall buy a pack of those from the link you gave and give them a try, then add the results to the article when I photograph the built prototype.
Thank you once more for the info. Much appreciated.
VBR Harry
_________________
Everything in this world is either bacon, or it isn't bacon
They say that money cannot bring you happiness, but if you have it then you can always buy more bacon
Re: New project on HHH http://sm0vpo.altervista.org/ (www.sm0vpo.com later)
Hi all,
if you want to replicate the original design with a thermistor, it can be still available for fair prices e. g. here They are 50 mW rated and packed in epoxy.
VBR from Ivan
if you want to replicate the original design with a thermistor, it can be still available for fair prices e. g. here They are 50 mW rated and packed in epoxy.
VBR from Ivan
Ivan- Posts : 792
Join date : 2012-11-25
Age : 64
Location : Praha, Czechia
New project on HHH http://sm0vpo.altervista.org/ (www.sm0vpo.com later)
Hi Guys,
Just added another new project on HHH. The same as before, I have only been able to add it to http://sm0vpo.altervista.org/ because I don't have FTP access to www.sm0vpo.com.
The "new" project is an old design Audio Frequency Generator. All the design is complete. I built this project about 30 years ago (or was it more?). I had it for years, but it went in the house moving, downsizing and such. But I am really missing it.
Some of the older components were difficult to get 30 years ago, but today you have to throw money at them. There is an alternative :-)
See: http://sm0vpo.altervista.org/audio/af-gen_01.htm
Sorry it is a bit long-winded. It was planned and designed while I was in Spai, but I hope to build it shortly. I will post the pictures/photos and any possible corrections.
I bought a piller drill today, so I can now drill holes in PCBs The only other drill I had access to was at work, costs US$60,000 and the interlocks will not let me hold a PCB in my hand!!
Enjoy - BR Harry SM0VPO
Just added another new project on HHH. The same as before, I have only been able to add it to http://sm0vpo.altervista.org/ because I don't have FTP access to www.sm0vpo.com.
The "new" project is an old design Audio Frequency Generator. All the design is complete. I built this project about 30 years ago (or was it more?). I had it for years, but it went in the house moving, downsizing and such. But I am really missing it.
Some of the older components were difficult to get 30 years ago, but today you have to throw money at them. There is an alternative :-)
See: http://sm0vpo.altervista.org/audio/af-gen_01.htm
Sorry it is a bit long-winded. It was planned and designed while I was in Spai, but I hope to build it shortly. I will post the pictures/photos and any possible corrections.
I bought a piller drill today, so I can now drill holes in PCBs The only other drill I had access to was at work, costs US$60,000 and the interlocks will not let me hold a PCB in my hand!!
Enjoy - BR Harry SM0VPO
_________________
Everything in this world is either bacon, or it isn't bacon
They say that money cannot bring you happiness, but if you have it then you can always buy more bacon
Similar topics
» http://sm0vpo.altervista.org/
» Changes to www.sm0vpo.com (and sm0vpo.altervista.org)
» Yet another new project on www.sm0vpo.com
» New project on www.sm0vpo.com - For IVAN
» New project on www.sm0vpo.com - Basic HF / VHF filters
» Changes to www.sm0vpo.com (and sm0vpo.altervista.org)
» Yet another new project on www.sm0vpo.com
» New project on www.sm0vpo.com - For IVAN
» New project on www.sm0vpo.com - Basic HF / VHF filters
Page 1 of 1
Permissions in this forum:
You can reply to topics in this forum
|
|