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5 years, 6 months ago
КТ315 — A working horsy of domestic electronicsThough I also was late for day of Radio — but about КТ315 I will write all. This transistor saw and soldered many, but today we will see, than differ КТ315 let out in different years, what its design, and we will compare its design to modern foreign analogues.

About manufacture

КТ315 — The first transistor made on a last word in fashion of the end of 60th years is planarno-epitaksialnoj the transistor, i.e. a collector, the emitter and base are produced consistently on one plate of silicon: the plate of silicon alloyed in type n (it will be a collector) undertakes, then is carried out legirovanie on some depth in type p (it will be base), and then — from above once again legirovanie on smaller depth in type n (it will be the emitter). Further the plate needs to be cut on slices, and to pack into the plastic case.

КТ315 — A working horsy of domestic electronicsSuch process of manufacturing was much cheaper than floatable technology, and allowed to receive inconceivable earlier transistor parametres (in particular, working frequency of 250-300 MHz).

The following novelty which has led to reduction in price of manufacture — crystal installation not in the metal case, and on a metal tape with conclusions: a crystal on which bottom party the collector was soldered to the central conclusion, and the base and the emitter — were connected by a welded wire. Then all it was filled in with plastic, superfluous details of a tape were cut off — and it turned out КТ315 such what we have got used to see it.

Explanatories to drawing on the right: and — skrajbirovanie and division of a plate into crystals with ready structures; — the soldering of crystals to a tape; in — conclusion joining; g — a tape scrap; d — hermetic sealing; e — extraction from the form; — a scrap of a tape and division of diodes/transistors; 1 — a tape; 2 — a crystal; 3 — a crystal conclusion

The batch production has begun in 1967-1968, for mere mortals the price at first made 4 roubles for the transistor. But already in the mid-seventies it has fallen to 15-20 copecks, as has made it on the present the accessible transistor. At the salary of the engineer in 120 roubles — it was possible to buy 600 transistors in a month. By the way, now for the conditional salary of the engineer in 45тыс roubles it is possible to buy 121'000 transistors BC856B so the transistor standard of living of the engineer has grown in 201 times КТ315 — A working horsy of domestic electronics

It is remarkable that the first devices collected on КТ315 — transistor (microcircuits only grew) "calculators" Electronics DD and Electronics 68.

Here such meeting was found out in me:

КТ315 — A working horsy of domestic electronics
Where there is no sign on factory of the manufacturer is КТ361, pnp a variant. The others, with a logo — КТ315 (even if «a letter on the centre»). It is remarkable that at the time of a planned economy, the fixed prices, and formal absence of gamble — the price sometimes wrote directly on transistors.

What inside?

The oldest transistor which at me was — КТ315А, let out in March, 1978.
We see that the crystal is broken off from a plate far not ideally, round the transistor — a lot of not used place.

Here the crystal is a collector, in the centre if I am not mistaken — base mugs, and round it — wider "belt" of the emitter. The base as podnyrivaet under the emitter, also leaves from a ring underside.

КТ315 — A working horsy of domestic electronics

Further, we will look on КТ315Г, made in February at 92nd, after 14 years of evolution.

Here at once it is visible that the place is spent much more economically, a crystal critical defects of a photolithography are cut off almost ideally, appreciable small not, probably the contact photolithography here is still used. However, it is quite enough for transistors of it.

КТ315 — A working horsy of domestic electronics

And at last, КТ361Г, July, 1984.

КТ315 — A working horsy of domestic electronics


If to compare in scale to modern transistor NXP BC847B it is visible that the size it was possible to reduce still time in 2 for the account "okvadrachivanija", but the transistor essentially has not changed — the same collector at "bottom" of a crystal, and the conclusions of the emitter welded by a wire and bases.

It is remarkable that at BC847 the width/height of a crystal is almost equal to a thickness of a plate, it already almost silicon cube, instead of a plate. To reduce the area it is inconvenient further, at least without further utonenija plates (utonenie plates — it is written correctly).

КТ315 — A working horsy of domestic electronics

The future

Whether has died КТ315? Definitely not. Till now it is for example in Integral price-lists on 248 Belarus roubles (~1 Russian rouble), i.e. it is probable still in manufacture. Certainly, with development of automatic installation of printed-circuit boards had to make way for it SMD-variants, for example КТ3129 and КТ3130 and many other things, including to foreign analogues BC846-BC848, BC856-BC858.

But in our memory it remains for ever:-)

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