|
Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
|
Thread Tools |
27th May 2014, 8:17 am | #1 |
Hexode
Join Date: Jan 2006
Location: Greater Manchester, UK.
Posts: 373
|
Modern Equivalent Thermistor
What would be the modern equivalent of STC R53 thermistor?
|
27th May 2014, 9:14 am | #2 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,801
|
Re: Modern Equivanlent Thermistor
There isn't.
I assume it's for a wien bridge oscillator? Later designs went for rectifier and variable resistance FET control. Earlier designs ran higher power and used a small light bulb ('Bill's Bulb') Current audio source designs compute phase then use a sine look up table in ROM and stuff the result into a DAC and filter. David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |
27th May 2014, 9:48 am | #3 |
Octode
Join Date: Jul 2009
Location: Carmel, Llannerchymedd, Anglesey, UK.
Posts: 1,498
|
Re: Modern Equivanlent Thermistor
A pity this is no longer available. I have used a number of these in the past and it is possible to construct an oscillator which is stable, simple and uses a handful of components, yet manages to produce distortion below 0.05%. I suppose the easiest route these days would be the overkill of using a DDS device, but as wrangler has stated - a filter would then be required to get a really good distortion figure.
Progress? I rather think not! |
27th May 2014, 4:38 pm | #4 |
Hexode
Join Date: Jan 2006
Location: Greater Manchester, UK.
Posts: 373
|
Re: Modern Equivalent Thermistor
Oh well never mind, will have to go new school route for signal source and use Audacity. Generating the frequency that I desire to control the motor on a loop. Or alternatively record the signal to tape and use my Ferrograph continuous loop tape spool to do the controlling.
That's as technical as it gets for me, I know there is a whole raft that you can now do in the digital domain but out of my scope. The Heathkit AG-9 needs a complete refurb but that uses the 3 watt 120v bulb in the feedback circuit. But that will have to wait for another day. |
27th May 2014, 7:04 pm | #5 |
Rest in Peace
Join Date: Feb 2004
Location: Hexham, Northumberland, UK.
Posts: 2,234
|
Re: Modern Equivalent Thermistor
I have an R23 and an R52 thermistor if you think they are near enough equivalents to be of any use. They are both tubular glass about 25mm long by about 10mm across.
Alan. |
27th May 2014, 8:54 pm | #6 |
Octode
Join Date: Dec 2008
Location: Wincanton, Somerset, UK.
Posts: 1,757
|
Re: Modern Equivalent Thermistor
The R23 looks pretty close: an R53 circuit would just need a small change to one resistor value to accomodate.
John |