211
2.87 Acoustic continuity tester
Circuit 186:
Acoustic continuity tester
Setup information
Install the two transistors, the four resistors and the two ceramic capacitors as shown in
Fig. 2.186
followed
by the eight jumper wires. Finally connect the Piezo element connect the Piezo element. Check the place-
ment 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,
2 x 2.2 k
Ω
resistors,
2 x 220 k
Ω
resistors,
2 x 1 nF ceramic capacitor,
1 x 1 μF electrolytic capaci-
tor, 1 x Piezo element,
1 x breadboard, 1 x 9V bat-
tery with clip connector
Fig. 2.186:
Acoustic continuity
tester
Experiment
Even if everything is wired correctly, you won’t hear anything at first. But by bridging, the test leads become
low-resistance and you will hear a loud tone. This makes continuity measurements easy and straightfor-
ward.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.186.
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...
