It is currently Sat Jun 23, 2018 8:48 pm

bag of bits

 
Posts: 2513
Joined: Sun Jun 10, 2012 7:23 pm
Location: Basildon

bag of bits

Post by crackle » Tue Mar 03, 2015 12:15 pm

I bought a bag of components from the bring and buy stall at Harpenden.

There were some interesting components that I have not come across before.
Here are a few.

I thought it unusual to see small diodes in a metal can, open at one end. The body is about 5mm long. I cant find any reference to the CV number, it must be highly top secret.
Img_3803 diode.jpg


The black resistor is 499k (light reflection makes it look like 429) obviously 500k was not precise enough for the circuit designers, it should be useful for checking the high ranges of my DMM, and the pink resistor should be useful for checking the low ranges.
Img_3803 resistor.jpg


This object which looks like a multi tap power resistor has me puzzled. What is it and how do those measurements work out :bbd
Img_3803 S2s.jpg


I originally thought this was just a glass tube, then I noticed it does appear to have something inside it. You can just see the tiny little bead just under the second T in "Thermistor" and the almost invisible wires coming from each side of the bead. There are no external connections outside of the glass tube so I am assuming the glass tube is just protective packaging and would be broken to remove the thermistor from the inside. As a scale the glass tube is about 3mm diameter.
thermister micro.jpg


Oh, and these cup things which look like some sort of ceramic, what are they? They fit nicely on the tips of my fingers and are good at annoying every one if I drum my fingers on the desk. :bba . The writing on it looks like LECO 12 and then repeated on the other side.
Img_3811 s.jpg


Mike

 
Posts: 138
Joined: Sun Apr 13, 2014 2:47 pm
Location: Middlewich, On the canals, & Philippines

Re: bag of bits

Post by Boater Sam » Tue Mar 03, 2015 1:06 pm

What is on the ends of the glass tube? Looks like the thermal cut outs used on ceramic hobs. The glass expands when hot, the invar wire inside doesn't, the switch went on the end.
Ceramic things, crucibles?

 
Posts: 2513
Joined: Sun Jun 10, 2012 7:23 pm
Location: Basildon

Re: bag of bits

Post by crackle » Tue Mar 03, 2015 1:42 pm

Boater Sam wrote:What is on the ends of the glass tube? Looks like the thermal cut outs used on ceramic hobs. The glass expands when hot, the invar wire inside doesn't, the switch went on the end.
Ceramic things, crucibles?


The ends of the glass tube are sealed, it looks like the ultra thin wavy wire inside the tube stops short of the ends.
Mike

 
Posts: 2513
Joined: Sun Jun 10, 2012 7:23 pm
Location: Basildon

Re: bag of bits

Post by crackle » Tue Mar 03, 2015 1:42 pm

ppppenguin wrote:Fairly sure the CV diode is a zener. Power supply, resistor and meter should confirm that.


Ill give that a check.

mike

 
Posts: 1898
Joined: Mon Jul 25, 2011 12:12 pm
Location: Burghfield, Reading, UK

Re: bag of bits

Post by Briancuff » Tue Mar 03, 2015 2:56 pm

The thermistor looks like a fast acting thermistor for use in feedback loops. The original Mullard transistor audio oscillator used an R36? in a feedback loop to control the output level. It is in vaccuo so that ambient temperature has little effect on it, only the current through it.

 
Posts: 917
Joined: Sat May 26, 2012 5:41 pm

Re: bag of bits

Post by Valvebloke » Tue Mar 03, 2015 3:19 pm

Crackle wrote:... This object which looks like a multi tap power resistor has me puzzled. What is it and how do those measurements work out :bbd
Img_3803 S2s.jpg
...


I'd be very, very careful with this. It appears to be the property of The Mysterons :ccf .

EDIT: I think the measurements are explained by it not actually being multi-tapped. Instead it consists of four separate resistors, each having one end connected to the centre wire (wire number 3 if you number them 1, 2, 3, 4, 5 from left to right). So 1-3 is 150, 2-3 is 514, 4-3 is 381 and 5-3 is 891. All the other measurements are made up, as near as d@mm!t, by adding these up. So 1-2 is 1-3 + 3-2.

VB

 
Posts: 2513
Joined: Sun Jun 10, 2012 7:23 pm
Location: Basildon

Re: bag of bits

Post by crackle » Tue Mar 03, 2015 3:55 pm

And today's star prize goes to VB, well done, you have cracked it. The odd inaccuracies must be my meter readings and dirty wires.
What a weird contraption, and strange way of packaging 4 resistors wired to a common point.

Mike

 
Posts: 2513
Joined: Sun Jun 10, 2012 7:23 pm
Location: Basildon

Re: bag of bits

Post by crackle » Tue Mar 03, 2015 4:12 pm

Brianc wrote:The thermistor looks like a fast acting thermistor for use in feedback loops. The original Mullard transistor audio oscillator used an R36? in a feedback loop to control the output level. It is in vaccuo so that ambient temperature has little effect on it, only the current through it.


If there were end caps fitted to it that would seem to make sense. But I have just studied it with a more powerful eye glass and it dosen't look like the ultra thin wire goes through the molten sealed ends of the glass tube. I can clearly see that one end only reaches to within 15mm of the end, the other end looks to be touching the inside edge of the molten glass but not passing through.

Mike

 
Posts: 2513
Joined: Sun Jun 10, 2012 7:23 pm
Location: Basildon

Re: bag of bits

Post by crackle » Tue Mar 03, 2015 4:22 pm

ppppenguin wrote:Fairly sure the CV diode is a zener. Power supply, resistor and meter should confirm that.

Just checked the volt drop and the CV8261 is 0.54v. There is a single other diode in a can which looks like an AC128 package but painted black with an arrow on it together with the markings CV5099, this measures 0.72v, so does that make it germanium and the first diode is silicon.

Mike

 
Posts: 2513
Joined: Sun Jun 10, 2012 7:23 pm
Location: Basildon

Re: bag of bits

Post by crackle » Tue Mar 03, 2015 4:46 pm

ppppenguin wrote:You've measured the forward voltage drop of the propective zener. It will look like an ordinary diode. For a zener you need to find the reverse breakdown voltage.


I have just tried again with 100v supply and 8.2k resistor and there is no sign of any zener action, I measure 0.6v one way round and if diode is reversed I get 100v.

Mike

 
Posts: 6972
Joined: Sun Aug 14, 2011 11:02 am
Location: Co. Limerick

Re: bag of bits

Post by Michael Watterson » Tue Mar 03, 2015 4:52 pm

glass tube is just protective packaging and would be broken to remove the thermistor from the inside. As a scale the glass tube is about 3mm diameter.

There ARE thermistors mounted like that. To keep out damp. It's less common than a thermistor in a point of a glass tube.

 
Posts: 27
Joined: Sun Feb 10, 2013 11:34 am
Location: Forest of Dean

Re: bag of bits

Post by Stockden » Tue Mar 03, 2015 5:00 pm

According to the "CV Register of Electronic valves 1963" (here: http://www.tubecollector.org/cv/1963/) CV 8261 is a "semiconductor rectifier" and is equivalent to ZS32B. A web search for ZS32B suggests that's a 600V 1A device (or, to be precise, ZS32B can be replaced by a 600V 1A device).

CV5099 is also described as a rectifier and is equivalent to ZS22 and CV4078

Hugh

 
Posts: 2513
Joined: Sun Jun 10, 2012 7:23 pm
Location: Basildon

Re: bag of bits

Post by crackle » Tue Mar 03, 2015 5:23 pm

Hi Hugh

Thanks that is useful to know.

Mike

 
Posts: 3712
Joined: Sun Feb 12, 2012 7:43 pm
Location: North Hykeham, Lincolnshire and Ilford, Essex (but not for much longer ...!)

Re: bag of bits

Post by Terrykc » Tue Mar 03, 2015 5:56 pm

Crackle wrote:... The black resistor is 499k (light reflection makes it look like 429) obviously 500k was not precise enough for the circuit designers ...

Sorry, Mike. Wrong answer!

Remember this?

Image
It contains all the values that the average VRAT is likely to meet and shows how the values dovetail together as the tolerances get tighter.

However, some people need even tighter tolerances and simply adding extra values into the left hand column would give a range which wouldn't quite blend together so neatly, so the ranges had to be tweaked slightly for a better fit.

If we go up a range further, we get these values:

E48 Range
1.001.051.101.151.211.27
1.331.401.471.541.621.69
1.781.871.962.052.152.26
2.372.492.612.742.873.01
3.163.323.483.653.834.02
4.224.424.644.875.115.36
5.625.906.196.496.817.15
7.507.878.258.669.099.53

Still not enough for your new resistor, so we need to go up yet another range!

E96 Range
1.001.021.051.071.101.13
1.151.181.211.241.271.30
1.331.371.401.431.471.50
1.541.581.621.651.691.74
1.781.821.871.911.962.00
2.052.102.162.212.262.32
2.372.432.492.552.612.67
2.742.802.872.943.013.09
3.163.243.323.403.483.57
3.653.743.833.924.024.12
4.224.324.424.534.644.75
4.874.995.115.235.365.49
5.625.765.906.046.196.34
6.496.656.816.987.157.32
7.507.687.878.068.258.45
8.668.879.099.319.539.76

... and there is 4.99 (and decade multiples!) for you ...!


Return to General Work Shop Discussion



Who is online

Users browsing this forum: No registered users and 2 guests