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Mountain of USSR transistors

A mountain of old Soviet KT315 and KT361 transistors. Author: Dmitry G.

The ideaEdit

It was the USSR's first indigenous designed transistor.


Probably akin to the then going western semi-conductor etching practices.


Soviet КТ315 NPN bipolar junction transistor.
Category. Statistic.
Designed in. Early 1970's.
Made in. 1973.
Transistors per chip. 1.
Power supply. Low.
Still in use. Yes, in surplus Soviet equipment and some older Russian stuff.
Nationality. Soviet.
Transistor KT315

A Soviet transistor KT315 diagram.

  • Name- КТ315 А…И.
  • Structure- n-p-n.
  • Uce- 15 — 60 V.
  • Ube- 6 V.
  • Ic- 50 — 100 mA.
  • Ib- 50 mA.
  • P- 100 mW.
  • Pmax- 150 mW.
  • Tmax, °C- up to 100 °C.
  • fгр- 250 MHz.
  • h21e- 20 — 350.



Some Soviet KT315b transistors. Author: Dmitry G.

A 3 metal legged precast solid resin capsule.


The KT315 is a Soviet NPN bipolar junction transistor used for general purpose low-power amplifying or switching applications, performed in the plastic KT-13 case. It has been widely used in the Soviet electronic equipment. A KT361 is a complementary (PNP) for the KT315 transistor, so it often used with it in a pair in push-pull circuits.

KT315 and KT361 transistors became the first in the USSR, which were produced by planar technology. RThe ratio of the parameters reached in the KT315 was a breakthrough at that time. Such 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 development of KT315 was awarded with the USSR State Prize in 1973. It was one of the Soviet's first moves in to the modern electrical business and it was seen as a national icon at the time.


KT315 transistors were designed for use in amplifier circuits of high, medium and sound frequencies.

See also Edit

  • 2N3904 — NPN transistor with slightly better specifications than KT315. Usually can be used as a replacement.
  • 2N3906 — PNP transistor with slightly better specifications than KT361. Usually can be used as a replacement.

References Edit

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