Velleman EDU01 - Manual (Page 7)

www.vellemanprojects.com Pag. 7
Transistors
A transistor is an amplification device. By means of a small
current, a much larger current is controlled. Transistors come in
two flavours, 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)
LDR (Light Dependent Resistor)
E B C
C
B
E PNP
C B E
C
B
E NPN
BC547
BC557
A Light Dependent Resistor behaves
like a resistor. The resistance various
on the amount of light falling on the
device, it decreases with increasing
light intensity.
Velleman part# LDR04)