110
2.34 Fog horn
Circuit 85:
Fog horn
Setup information
Install the two transistors, the five resistors and the two electrolytic capacitors as shown in
Fig. 2.85.
The
nine jumper wires come next. Last but not least, 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 1 k
Ω
resistor,
2 x 2.2 k
Ω
resistors,
2 x 47 k
Ω
resistors,
2 x 100 nF ceramic capaci-
tors, 1 x 10 μF electrolytic
capacitor, 1 x 1000 μF elec-
trolytic capacitor, 1 x Piezo
element, 1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.85:
Fog horn
Experiment
If everything is wired correctly, you will hear a slowly rising raucous sound similar to a foghorn once the
battery is connected. When you switch off the battery, the sound slowly fades away. However, over the Piezo
element the sound is not as powerful as the original, but sufficient for your tests.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.85.
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...
