65
Circuit 40:
High pass from on 5.5 kHz
Setup information
Install the transistor and the three resistors as shown in
Fig. 2.40.
Then install the two ceramic capacitors
and the electrolytic capacitor. The five jumper wires come next. Finally connect the Piezo element. Check
the placement on the board again and only then connect the battery.
You can increase the sensitivity of the Piezo element significantly by using a sound plate or even a sound
box. Read more about it in Chap. 1.2.3
Components required:
1 x 2N3904 transistor,
1 x 2.2 k
Ω
resistor,
1 x 22 k
Ω
resistor,
1 x 100 k
Ω
resistor,
2 x 10 nF ceramic capaci-
tors, 1 x 10 μF electrolytic
capacitor, 1 x Piezo ele-
ment, 1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.40:
High pass 5.5 kHz
onwards
Experiment
A high pass filter lets high-pitched tones pass through and blocks deep tones. In our circuit, only signals
with a frequency above 5.500 Hz can pass through. Connect the output of an mp3 player to the input.
You often can’t hear the music played – very high-pitched sounds are rare. Voice recordings can’t be distin-
guished at all. The limit of the cut-off frequency is determined by the values of C1, C2 and R2.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.40.
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...
