Active Probe - Maker Factory ELECTRONICS EXPERIMENTS BOX Manual

2.89 Active probe

Circuit 189: Simple active probe with Piezo element
Setup information
Install the transistor, the three resistors, the ceramic capacitor and the three electrolytic capacitors
Fig. 2.189 followed by six jumper wires. Last but not least 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
The active probe operates within a frequency range from 100 Hz to approximately 1 MHz. If our circuit is
used within the NF range, you will hear the signal coming from the Piezo element.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.189.
214
Components required:
1 x J111 FET transistor,
1 x 2.2 kΩ resistor,
1 x 4.7 kΩ resistor, 1 x 1 MΩ
resistor, 1 x 10 nF ceramic
capacitor, 1 x 10 μF elec-
trolytic capacitor, 1 x Piezo
element, 1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.189: Simple active probe
with Piezo element