Cumpar ICM7556IPD

[Vizitator tinelush]

Vreau si eu sa cumpar integratu asta (ICM7556IPD) da se pare ca nu pot sa l gasesc . Am o schema in care trebuie obligatoriu acest integrat si nu un inlocuitor al lui . Rog pe cei care au asa ceva sau care stiu de unde pot sa l iau sa ma contacteze.

[Vizitator Florin]

Ai incercat la "Conex "Electronics pe strada Maica Domnului, Piata Lacul Tei?

[Vizitator tinelush]

Nu l am gasit pe site ul lor. Deci inca mai caut. :?

[cniky]

Nu l am gasit pe site ul lor. Deci inca mai caut. :?

deci da-le un email, sau incearca si la Vitacom... :wink:

[Vizitator tinelush]

Acest IC este un timer dual destul de banal (poate mosfet) asa ca sigur poti folosi in locul lui un simplu NE556 .

Acum sa lamuresc pe toata lumea : Vreau sa construiesc un detector de metale, destul de simplu , a carui schema am gasit o pe net . Cu toate ca in descrierea circuitului scria clar sa NU folosesc NE556N eu l am cumparat si apoi (Cu toate ca trebuia inainte) i am scris un mail celui care a pus scema pe net .... si el mi a raspuns : Thanks for the e-mail. No the NE556N won't work, that's a bipolar device, not CMOS. But the ICM7556IPD (CMOS) is freely available, it's not a rarity, so you should be able to find it without too much trouble. In some cases, the two are interchangeable, but not in this circuit. Acum sper sa ma credeti .... Si acum o mica paranteza despre super serviciile firmelor serioase de la noi din tara : Am trimis cate un email acum 4 zile la fiecare firma pe acare am gasit o pe net in legatura cu integratu asta (Conex electrinic , Adelaida ..... etc) si am trimis cate un mail si la niste firme din Germania , USA ,Canada .... De la firmele din Romania nu am primit nici pana astazi un raspuns fie el bun sau rau .... in schimb firmele straine mi au raspuns imediat cu toate informatiile necesare . Concluzie ...... : Copii nu mai bateti cuie in geam !!!!!!!!!!Inca mai caut integratul

[Vizitator tinelush]

Asta e link ul cu schema + constructie + explicatii :

http://www.siliconchip.com.au/cms/A_30558/article.html

 

Sa speram ca o sa se gaseasca o solutie ...

[Vizitator tinelush]

Ciudat ..... de pe google ma lasa sa intru direct in articol si de pe forum nu ma lasa ...... nu am mai intalnit ceva asemanator ....

 

An IB metal locator is usually far more complex than the design shown here - the EE-Magenta Buccaneer, for example, uses more than 70 components. This one uses less than 20.

 

The reason for the simplicity is that I have dispensed with analog circuitry, and instead used a digital transmitter and receiver.

 

As the search coils pass over metal, only digital signals of a certain amplitude break through to a peak detector (IC1b). Since these are in the audio range, they are immediately transferred to the piezo sounder or headphones.

 

On testing the sensitivity of this design in air, with optimal tuning and using a 25mm-diameter brass coin, it gave a clear signal at 150mm, and a 'screaming' signal at 110mm. It was also able to detect a pin at 30mm.

 

Note that these figures may not apply in the ground, where depth of penetration will depend largely on the mineralisation present.

 

In contrast, the locator is far more reluctant to pick up tin foil. A tin foil disk of the same size as the brass coin was only detected at half the distance in air. This rejection of tin foil is due in part to the metal locator's low frequency, which avoids what is called skin effect.

 

Besides this, if the two coils are positioned as described, ferrous metals (iron) are, to a very large extent, rejected - to such an extent, in fact, that a 25mm diameter brass coin weighing seven grams looks the same to the metal locator as a lump of iron weighing 20 times as much. Large non-ferrous objects are detected at half a metre distance and more.

 

The locator's power consumption is conveniently low. It draws around 10mA, which means that it may be powered off a small 9V battery. If an alkaline battery is used, this will provide about 48 hours' continuous use. In my experience, the number of coins that are found on a beach in an hour or two should easily make up for the cost of batteries!

 

Finally, while the stability of the locator is not the best, it's by no means the worst either. Re-tuning is necessary from time to time, especially in the first few minutes of use. One soon becomes accustomed to giving the Fine Tune knob an occasional tweak - perhaps with every 40 or 50 sweeps of the search head.

 

 

Circuit description

The search head of a typical IB metal locator contains two coils: a transmitter (Tx) coil and receiver (Rx) coil.

 

In this case, the Tx coil is driven by a square wave oscillator, which sets up an alternating magnetic field in the coil. The Rx coil is then positioned in such a way that it partly overlaps the Tx coil. By adjusting the amount of overlap, a point can be found where the voltages in the Rx coil 'null' or cancel out, so that little or no electrical output is produced. A metal object which enters the field then causes an imbalance, resulting in a signal.

 

The transmitter (IC1a) is a standard 555 oscillator configuration, using one half of the ICM7556IPD dual low power CMOS version of this IC.

 

Do NOT use the veteran NE556N IC, by the way.

 

IC1a oscillates at about 700Hz, determined by R/C components around pins 1, 2 and 6. The 680Ω resistor limits the current passing through the Tx coil.

 

The receiver section (IC1b) is preceded by a simple yet sensitive pre-amplifier stage, based on Q1, which amplifies the signal received from the Rx coil. This is fed directly to IC1b, which is used here as a high-performance sine-square convertor. Its input at pins 8 and 12 is biased by the divider formed by the 10kΩ resistor and pots VR1-VR3, so that only pulses of a certain amplitude break through to output pin 9.

 

There is a point at which, with careful adjustment, the signal is just breaking through in the form of a crackling sound. When the locator's output is adjusted to a fast crackle, the presence of metal turns this into a 'scream'. This is heard from the piezo sounder or through standard headphones. The 7556 IC allows up to 100mA of output current, therefore no further amplification is required.

 

 

E mai multa descriere dar nu pot sa o pun toata aici.

Cauta cu google "veteran NE556N" si o sa gasesca doar un link care te va duce in tot articolul .... inca nu pot sa mi explic de ce se intampla asa .....

Sper ca se vede schema acum .

[Vizitator tinelush]

Nu am placuta dar am montajul facut pe o placa de test ceva de genul asta :

 

Nu am nici cu ce masura fracventa ... dar explica akolo in articol ce trabuie facut pas cu pas. Deci parerea mea e ca daca omu zice sa NU se folosesca NE556N eu cred ca trebuie ascultat . Ceva modificari cu 2 ICM555 cum ziceai tu nu merge ?

Deci eu am facut circuitul dar dupa cum ai vazut e destul de greu la partea bobinelor si nu o sa ma apuc sa le fac pana nu gasesc o solutie sigura cu integratu .

[Vizitator tinelush]

) .. n am mai intrat de mult pe forumul asta . dabia acum am vazut postul . Diametrul nu trebuie neaparat identic , poti sa folosesti alta sarma cu diametru apropiat ( incerca sa faci rost de sarma din bobina de la tuburi de TV delea mai vechi ca o sa ti trebuiasca multa ). Da mi si mie mai multe detalii cum sa cumpar ICM ul ala . Astept un mesaj la messenger4pil @ yahoo.com si daca mai gasesc o sa ti trimit toate informatiile care le am despre detectorul asta.