Storm Detector - Maker Factory ELECTRONICS EXPERIMENTS BOX Manual

2.24 Storm detector

Circuit 57: Amplifier for a storm detector
Setup information
Install the two transistors and the four resistors as shown in Fig. 2.57. Next install the three electrolytic
capacitors followed by the six jumper wires. 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
This circuit intends to amplify lower audio signals by about 2,000 times. That is how the low-intensity
electromagnetic pulses arriving from far away lightning discharges are made audible. If you still own a radio
with LW or MW reception, you can experience yourself what is happening on the acoustical level during a
local thunderstorm. Switch to MW or LW and search for a setting where nothing is broadcasted. With every
bolt of lightning you can hear more or less loud cracking and crackling.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.57.
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Components required:
2 x 2N3904 transistors,
1 x 1 kΩ resistor, 1 x 10 kΩ
resistor, 1 x 47 kΩ resistor,
1 x 100 kΩ resistor, 1 x 1 μF
electrolytic capacitor,
1 x 10 μF electrolytic
capacitor, 1 x 100 μF elec-
trolytic capacitor, 1 x Piezo
element, 1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.57: Amplifier for a storm
detector