137
Circuit 112:
Glass breakage detector
Setup information
Install the three transistors, the diode and the six resistors as shown in
Fig. 2.112
The twelve jumper wires
come next. Last but not least connect the Piezo element. Check the placement on the board again and only
then connect.
Components required:
2 x 2N3904 transistors, 1 x 2N3906 transistor, 1 x red LED,
1 x 1 k
Ω
resistor, 2 x 10 k
Ω
resistors, 1 x 47 k
Ω
resistor,
2 x 470 k
Ω
resistors, 1 x 1 μF electrolytic capacitor, 2 x 10 μF
electrolytic capacitors, 1 x Piezo element, 1 x breadboard,
1 x 9V battery with clip connector
Fig. 2.112:
Glass breakage detector
Experiment
If everything is wired correctly, the small signals of the Piezo element, which in our case represents a micro-
phone, will be strongly amplified. At a certain threshold the red LED indicator turns on. The circuit is very
responsive to the noise of breaking glass. You can significantly increase the sensitivity of the Piezo element,
which is used as a microphone by using a sound plate or even a sound box. Read more about it in Chap.
1.2.3. That way you are able to monitor the breakage of glass panes, plus register other acoustic events
(thunder, loud air traffic and car noises, dog barking, etc.).
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.112.
Содержание ELECTRONICS EXPERIMENTS BOX
Страница 4: ......
Страница 251: ...253 Fig 3 27 Circuit 27 4 seconds switch off delay Fig 3 28 Circuit 28 20 seconds switch off delay...
Страница 258: ...260 Fig 3 42 Circuit 42 Active 8 5V battery monitor Fig 3 43 Circuit 43 Active 7 8V battery monitor...
Страница 260: ...262 Fig 3 46 Circuit 46 Meters for 1 5 V Zener diodes and higher Fig 3 47 Circuit 47 Discreet 2 2V Zener diode...
Страница 261: ...263 Fig 3 48 Circuit 48 Discreet 2 9V Zener diode Fig 3 49 Circuit 49 Discreet 3 7V Zener diode...
Страница 265: ...267 Fig 3 56 Cir cuit 56 Audio limiter Fig 3 57 Circuit 57 Amplifier for a storm detector...
Страница 269: ...271 Fig 3 64 Circuit 64 Stabilizer for 1 9 V Fig 3 65 Circuit 65 Stabilizer for 2 5 V...
Страница 275: ...277 Fig 3 80 Circuit 80 Quiztimer 30 seconds Fig 3 81 Circuit 81 Handy diode tester...
Страница 290: ...292 Fig 3 118 Circuit 118 HF watch dog with LED indicator Fig 3 119 Circuit 119 HF watchdog with moving coil instrument...
Страница 295: ...297 Fig 3 130 Circuit 130 4 seconds switch on delay Fig 3 131 Circuit 131 15 seconds switch off delay...
Страница 298: ...300 Fig 3 136 Circuit 136 NAND gate with moving coil instrument Fig 3 137 Circuit 137 Input level Mixing console...
Страница 300: ...302 Fig 3 140 Circuit 140 Electrometer with moving coil instrument Fig 3 141 Circuit 141 Simple AM Radio...
Страница 315: ...317 Fig 3 179 Circuit 179 HF generator 150 kHz Fig 3 180 Circuit 180 HF generator 420 kHz...
Страница 324: ...326 Fig 3 202 Circuit 202 3 seconds switch on delay Fig 3 203 Circuit 203 7 seconds switch on delay...
Страница 325: ...327 Fig 3 204 Circuit 204 Piercing siren sound with Piezo element Fig 3 205 Circuit 205 Discrete Operational ampli fier...
Страница 328: ...330 Fig 3 210 Circuit 210 Discreet 5 2V Zener diode Fig 3 211 Circuit 211 Discreet 7 4V Zener diode...
