111
2.35 Mosquito repeller
Circuit 86:
Mosquito repeller
Setup information
Install the two transistors, the four resistors and the three electrolytic capacitors as shown in
2.86
followed
by the eight jumper wires. Last but not least connect the Piezo element.
Check the placement on the board again and only then connect the battery.
Components required:
2 x 2N3904 transistors,
2 x 1 k
Ω
resistors,
2 x 100 k
Ω
resistors,
1 x 220 k
Ω
resistor,
2 x 220 nF ceramic capaci-
tors, 1 x 10 nF ceramic
capacitor, 1 x Piezo ele-
ment, 1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.86:
Mosquito repeller
Experiment
If everything is wired correctly, you will not hear anything once the battery is connected. The sound waves
generated are in the frequency range of ultrasonic waves. Mosquitoes usually do not like this sound and
stay away. Now we hope you can leave your bedroom window open without being bothered by mosquitoes.
The Piezo element is not designed for such high frequency and therefore the volume is very low.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.86.
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...
