120
2.40 Loud foghorn
Circuit 95:
Fog horn
Setup information
Install the three transistors, the seven resistors and the two electrolytic capacitors as shown in
Fig. 2.95.
The twelve 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
Components required:
2 x 2N3904 transistors,
1 x 2N3906 transistor,
1 x 1 k
Ω
resistor,
2 x 2.2 k
Ω
resistors,
4 x 220 k
Ω
resistors,
2 x 10 nF ceramic capaci-
tors, 2 x 10 μF electrolytic
capacitors, 1 x Piezo
element, 1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.95:
Fog horn
Experiment
If everything is wired correctly, you will hear a loud raucous sound like that of a fog horn once the battery is
connected. The sound coming from the Piezo element is not as powerful as the original, but it is sufficient
for your tests.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.95.
Summary of Contents for ELECTRONICS EXPERIMENTS BOX
Page 4: ......
Page 265: ...267 Fig 3 56 Cir cuit 56 Audio limiter Fig 3 57 Circuit 57 Amplifier for a storm detector...
Page 269: ...271 Fig 3 64 Circuit 64 Stabilizer for 1 9 V Fig 3 65 Circuit 65 Stabilizer for 2 5 V...
Page 275: ...277 Fig 3 80 Circuit 80 Quiztimer 30 seconds Fig 3 81 Circuit 81 Handy diode tester...
Page 315: ...317 Fig 3 179 Circuit 179 HF generator 150 kHz Fig 3 180 Circuit 180 HF generator 420 kHz...
