Lighting & Signalling modules
11
Site: exxotest.com
B
C
E
+
L.E.D.
Type NPN
For the transistor to allow current to pass
The flow of the control current should be from the base to the emitter
The flow of the current should be from the collector to the emitter
The advantages of transistors:
- Can be controlled by a frequency of several megahertz
- Practically indestructible
- No induced currents
- Very low control current from emitter to base
- Instant disconnection
- Can be used as an amplifier
- Noiseless
Each transistor is characterised by its gain. This is a
coefficient which is used to determine the level of
current flowing through the power circuit, from emitter
to collector, based upon the current in the control
circuit, from emitter to base.
E.g.: for a gain of 100, if I
EB
= 0.1 A, then I
EC
will be 10A.
The transistor does not allow current to flow.
The transistor allows current to flow
B
E
C
+
-
+
E
B
C
+
+
-
B
C
E
+
L.E.D.
