Siren - Maker Factory ELECTRONICS EXPERIMENTS BOX Manual

2.96 Siren

Circuit 204: Piercing siren sound with Piezo element
Setup information
Install the two transistors, the five resistors and the two ceramic capacitors as shown in Fig. 2.204. The
fifteen jumper wires come next. Finally connect the Piezo element. Check the placement on the board again
and only then connect the battery.
You can significantly increase the sensitivity of the Piezo element by using a sound plate or even a sound
box. Read more about it in Chap. 1.2.3
Experiment
If everything is wired correctly, you will hear a piercing alert coming from the Piezo element.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.204.
Components required:
1 x 2N3904 transistor,
1 x 2N3906 transistor,
1 x 100 Ω resistor,
2 x 10 kΩ resistors,
1 x 22 kΩ resistor,
2 x 100 kΩ resistors,
2 x 100 nF ceramic capaci-
tors, 1 x 10 μF electrolytic
capacitor, 1 x Piezo ele-
ment, 1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.204: Piercing siren sound
with Piezo element
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