User Manual
7
Transistors
A transistor is an amplication device. By means of a small
current, a much larger current is controlled. Transistors come in
two avours, NPN and PNP-types, depending on the polarity. With
this kit, you receive a BC557 (PNP) and a BC547 (NPN) transistor. A
transistor has 3 pins: Base, Emitter and Collector. (Velleman part# BC557B,
BC547B)
Phototransistor
E B C
C
B
E
PNP
C B E
C
B
E
NPN
BC547
BC557
A phototransistor is a transistor
that conducts current when the
photocell inside it is sufficiently
exposed to light. You can use it as
a light switch in electrical cir-
cuits.
Velleman part# SGPT5053C )
E
C