Zahori

[Qiaozhi]

4066

Another important detail: the 4066 must be good quality, good level audio output. There are some low quality, no recommended.

Looks like this may be the source of the power supply problem then?

[Esteban]

No, put socket and try, and some Korean brands don't work well at the epoch I start with it, 10 years ago, so decide use Toshiba or any other Japanese brand as Hitachi, the both works fine, good level audio in the 3130 output.

Use Japanese because at the epoch I start found it in my market, no USA 4066 found, but now yes.

3130 is very obsolete, but is very sensitive and also very delicate, solder must be to ground.

[Qiaozhi]

3130 opamp

No, put socket and try, and some Korean brands don't work well at the epoch I start with it, 10 years ago, so decide use Toshiba or any other Japanese brand as Hitachi, the both works fine, good level audio in the 3130 output.

Use Japanese because at the epoch I start found it in my market, no USA 4066 found, but now yes.

3130 is very obsolete, but is very sensitive and also very delicate, solder must be to ground.

The CA3130E is a mosfet input, CMOS output opamp. You should be able to replace this with a CA3140E which is a mosfet input, bipolar output device.
I would also think that either an LF353N, OPA2604AP, TL072CN or TL082CN would be ok. The one with the lowest noise figure is the OPA2604AP at 10nV/Hz.

[Esteban]

Yes... but suspect the 3130 is more sensitive. If not, why they has been designed the Zahori at the time there are many more modern ICs, with less problem of offset?

Redesign the Zahori with low noise figure demands also film resistor resistance 1%.

[detectoman]

esteban, hola me puedes decir las aplicaciones de ese detector ionico su alcance sus limitaciones su estabilidad etc y tus experiencias con el

un saludo y hasta pronto

detectoman mexico

[robert]

.....

:confused:
Zahori is ment to be a ionic detection device, very old german project....
Already been seen some years ago in Elektor......What the hell is it usable in
metal detecting subject for!? Already known the fact that burried items do not
product any ions at all!

How many posts on such obsolete subject !?
Is that all man can find here on that subject!?

[Esteban]

Robert: I'm curious what version do you have, English, German, French? Evident, no as Zahori, this is a Spanish word. Or maybe you saw the first time here...

[robert]

Ha....!

Elektor CD from 1997/98....
German issue, i always purchase german issuess already....
Also there are editions on French,English and i guess Spanish (if you say so)...
regards

[Esteban]

What the hell is it usable in
metal detecting subject for!? Already known the fact that burried items do not product any ions at all!

Hard head, RObert! Always I show you the path... electric field around conductive metals! And the electric field can be detecable by the Zahori, with the corrects modifications. Also, Qiaozhi translate the text of the Zahori. As I see, nobody saw nothing in this thread. Read this part:

[Qiaozhi]

Zahori op amps

Yes... but suspect the 3130 is more sensitive. If not, why they has been designed the Zahori at the time there are many more modern ICs, with less problem of offset?

Redesign the Zahori with low noise figure demands also film resistor resistance 1%.

The main difference I can see between the CA3130 and the CA3140 is the input current and the equivalent input noise voltage.
CA3130 has Ii = 5pA @ 15V and 2pA @ 5V, and en = 23uV.
CA3140 has Ii = 10pA, and en = 48uV.
Not sure whether this would make a significant difference in this application. When you're talking about pA, there are plenty of other sources of interference to swamp these minute values of current.

[Esteban]

Qiaozhi:

Extracted info:

These are but a few of the low-cost operational amplifier models widely available from electronics suppliers. Most of them are available through retail supply stores such as Radio Shack. All are under $1.00 cost direct from the manufacturer (year 2001 prices). As you can see, there is substantial variation in performance between some of these units. Take for instance the parameter of input bias current: the CA3130 wins the prize for lowest, at 0.05 nA (or 50 pA), and the LM833 has the highest at slightly over 1 µA. The model CA3130 achieves its incredibly low bias current through the use of MOSFET transistors in its input stage. One manufacturer advertises the 3130's input impedance as 1.5 tera-ohms, or 1.5 x 1012 Ω! Other op-amps shown here with low bias current figures use JFET input transistors, while the high bias current models use bipolar input transistors.

Extracted from:

http://www.allaboutcircuits.com/vol_3/chpt_8/18.html

[Qiaozhi]

Qiaozhi:

Extracted info:

These are but a few of the low-cost operational amplifier models widely available from electronics suppliers. Most of them are available through retail supply stores such as Radio Shack. All are under $1.00 cost direct from the manufacturer (year 2001 prices). As you can see, there is substantial variation in performance between some of these units. Take for instance the parameter of input bias current: the CA3130 wins the prize for lowest, at 0.05 nA (or 50 pA), and the LM833 has the highest at slightly over 1 µA. The model CA3130 achieves its incredibly low bias current through the use of MOSFET transistors in its input stage. One manufacturer advertises the 3130's input impedance as 1.5 tera-ohms, or 1.5 x 1012 Ω! Other op-amps shown here with low bias current figures use JFET input transistors, while the high bias current models use bipolar input transistors.

Extracted from:

http://www.allaboutcircuits.com/vol_3/chpt_8/18.html

The CA3140 also has an input impedance of 1.5 Tera Ohm. It is very close to the CA3130 performance, and its not obsolete
I would think there are many other factors (such a poor PCB layout) that would have a bigger effect on the performance than the difference between these two devices.
Have you personally built this ion detector?

[Esteban]

Yes, I built. In some part of my labo is the PCB, all with sockets. The PCB I make by own hand, no with PCB program, 10 years ago or more. I'll search and send here the photo.

Remember I try the 3140, but perceive that the 3130 is better, I don't know why. I have this in plastic and metalic (CA3130T).

[robert]

pop


O.K. Esteban let's talk about Zahori for a while...
some remarks...:
- from your post"But in 1988 publish for positive and negative ions, looks that the zahori.
Article in Spanish. You can replace the plate by antenna."
Looking at the schematic you posted at the time i am not sure that 3130 will survive direct
connection to BC547 which at the same time provide plate polarisation!? Is this correct?
It will need some buffering and signal limitation at that point....
But, o.k. ...let's switch to the improved version you posted after that.
First instead headphones you put a cap and audio transformer at the same time you omited
scale. I do not think that output signal would be far enough to drive output transformer
and provide at least some usable tone. What you can hear is some "clicking" hum generated
from the 7555 due to poor filtering. About detection ....well, what we have here is a
wide range "detection" of noises and "airborne" hum , chopped by 7555 stage under very
strange, previously choosen, frequency rate!?
I am absolutelly sure that this device will produce some noise but not sure at all that
you can detect anything with it on longer range than 3-4 inches, and only if some
powerfull source of "signal" is placed nearby. The very same problems occurs with ivconic's
negative ion detector, although it is quite better design than zahori, at least it can
detect strong ionic field if nothing else.
O.K. I might be wrong considering this since i rely my remarks only on plain theory. I
never built zahori so far.
You made Zahori and i guess you do have some field experiences with it. Can you post here
exact reports from it?
"Hard head, RObert! Always I show you the path... electric field around conductive metals!
And the electric field can be detecable by the Zahori, with the corrects modifications.."
Thank you very much for "showing me the path"! Anyway....there is not any special electric
field around conductive metals to detect! It is a fact! Esspecially no such field around
burried metal, at all! There is for real an electrostatic field on the gnd surface and it
has for real very frequent changes, minute after minute. Those changes i guess you can
"detect" with zahori, maybe....maybe not...who knows?
"electric field around conductive metals" can be obtained only if that metal is in the area
covered by electromagnetic field generated by some source, that's how PI detectors do the job!
So it is not logical at all that you can use zahori and do the job is claimed to do. But
as i said, i never checked that in practice, i might be wrong....
I read this part again:
"We will describe how to assemble several components to construct an instrument that is able
to detect the variations in the electrical field, and indicate the ionic potential in the
immediate environment."
I cab beleive in that. But never mentioned any "conductive metals" at all! Only "variations
in the electrical field". It means that you can realy use zahori to trace changes across
some power line and simillar, and nothing else....
Further considerations are not important, device could work better or not - never mind.
The point is that zahori is not usable in this subject of metal detecting at all.
Sorry, but it is a truth! Besides i used so much 3130 and 3140 in my designs and i never
noticed such big difference among them at all. So far as i am concerned, the 709 would do
much better job than 3130 and 3140 in this design. Also some of newer rail to rail op-amps
could be much better solutions here. But what is the point!? To check electric field
variations you can do with some cheap "made in China" probes, you do not need to bug your
self with zahori at all!?
That's why i am using "obsolete" term here very often. I would like to see here some more
interesting project on that subject. I would post it if i had, but i do not yet.
I am not proponent and promoter of LRL, i am quite novice in that matter that's why i
provoked you to post here some more....
But, after all, it seems that you too, do not have any usefull project to post here.
Everything posted here man can assemble and check, than to beleive or not to beleive in
some claims. Otherwise all ends with an empty retorics.....
regards

P.S.
i hope this post is not offending you to much like in the past.....
ha,ha,ha...

[Esteban]

Regarding the ion detector for dual polarity, the both 4k7 resistence in base, one to negative load - reduces great the current, hope no motive for to think can burn the 3130.

Ok, in the Zahori, the 22 k controls the volume, note that in the original this is adjustable preset, no is fix in 22 k. So the volume is more high. Also you can up the 22 k, for example, to 47 k = more high volume. For to comprobe, you can ear the "hums" of the 4066 keys in the secondary (transformer) with earphones, but no connect yet any antenna, because in indoor is a "hell" (fluorescent lamps, cable, etc.). Adjusting the 10 k sens. pot. you can control the "hums" of the 4066 keys. The 10 k pot. put in the limit, in the start of the second stage audio circuit. This is a machine for indoor, far of electric lines and other interferences. So you put the most sensitive point with the 10 k of the Zahori. No synthetic clothes or plastic box for the instrument. I built in wood box (you can see in this same thread, page 2, the approximative model). Also Qiaozhi translate in English for all, in this same thread, the Zahori's text (0 views the both!) .


Of course, when you search with the 3 antennas instrument (indoor) you adjust with all the enviromental noise, internal ICs noise, 4066 "hums", etc. So over the level of the noise occurs the difference, this is the detection of the target. In some cases, noise is a reference wich put the "glitch" in delicate point, extremely sensitive. And the conductive buried target in the environment ups the microvolts in the antenna and sum. So, conductive items buried for long time has electrical field, no doubdt for me.


Don't try the 709 in this circuit, but the very high input impedance of the 3130 is the theme.

Also I redesign with 4047B as freq. generator and an only LM358. Works indoor, but I don't try in the field, yet.

Report? The only report I have of third part that found a gross heavy gold chain 1 m depth and 30 m far. Other person found antique woman comb carey and gold with gem stones, another found 4 gold coins, this same person found old wire for fences, entire roll! So, this mass of rolling wire has some thing... Is so impressive the signal, is difficult to center the objects.

The rest of the job is yours!

Here with the correct output:

http://www.mytempdir.com/707825