Conrad Course material 10090 14 years and over 10090 Manual De Usuario
Los códigos de productos
10090
The Transistor
Transistors are components to amplify small currents. The NPN transistor BC547B serves as speaker
amplifier. The transistor connections are called emitter (E), base (B) and collector (C). The base
connection is the middle one. The emitter is the right one when looking at the label with the
connections pointing down. The circuit symbol marks the base with a bar and the emitter with an
arrow. Observe the connections when installing. The flat labelled side points up towards the plus
line.
Build a wire switch between the base and collector. With the switch open, no current will flow
through the transistor and speaker. Therefore, there will not be any sound when you insert the
battery. Crackling is only audible when you switch a base current with the switch. Attention! The
base must only be short-circuited against the collector, but never against the battery plus pole.
amplifier. The transistor connections are called emitter (E), base (B) and collector (C). The base
connection is the middle one. The emitter is the right one when looking at the label with the
connections pointing down. The circuit symbol marks the base with a bar and the emitter with an
arrow. Observe the connections when installing. The flat labelled side points up towards the plus
line.
Build a wire switch between the base and collector. With the switch open, no current will flow
through the transistor and speaker. Therefore, there will not be any sound when you insert the
battery. Crackling is only audible when you switch a base current with the switch. Attention! The
base must only be short-circuited against the collector, but never against the battery plus pole.
Base Current
Find the resistor with 10 k
Ω . The resistor has coloured rings. Brown, black, orange means 10,000 Ω.
The fourth ring (gold) means tolerance class 5 %.
A resistor is used to reduce a current. In this case, the resistor leads to a base current of only about
0.1 mA. The transistor amplifies this small current by up to 300 times to about 30 mA. There is a
switch between the base and emitter of the transistor. When it is closed, it discharges the base
current. No collector current is flowing anymore either. Opening and closing of the contact therefore
generates a sound.
A resistor is used to reduce a current. In this case, the resistor leads to a base current of only about
0.1 mA. The transistor amplifies this small current by up to 300 times to about 30 mA. There is a
switch between the base and emitter of the transistor. When it is closed, it discharges the base
current. No collector current is flowing anymore either. Opening and closing of the contact therefore
generates a sound.