Variobot varikabi, Руководство пользователя

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The Transistors
A transistor is a simple electronic amplifier with three connections:
base (B), emitter (E) and collector (C).
At a sufficiently high voltage of about U
BE
= 0.7 V (V = Volt) between
base and emitter, the transistor reduces the resistance between
collector and emitter and - it is said - it switches through. The
collector current IC for ordinary transistors can be about 100 to 800
times larger than the base current I
B
.
varikabi uses Darlington transistors with a very high current amplification of
30 000. To supply the motor and LEDs with a current of 0.03 A (amps) = 30
mA (milliamperes), a base current of only 1
μ
A (microampere) is required:
30 mA / 30.000 = 0.001 mA = 1
µ
A
A Darlington transistor consists of two transistors connected in series and
requires about U
BE
=1.4 V instead of 0.7 V to switch through. To ensure that
the motors react to the sensor signals in opposite directions, varikabi uses a
complementary pair of transistors:
one PNP transistor for T
1
(BC516) and one NPN transistor for T
2
(BC517)
I
C
I
B
I
B
I
C
T
2
T
1