Table of Contents
Advertisement
Circuit 146: Simple signal tracker with Piezo element
Setup information
Install the two transistors, the five resistors and the four electrolytic capacitors as shown in Fig. 2.146 Insert
the eight jumpers. Last but not least connect the moving-coil instrument. Check the placement on the board
again and only then connect the battery.
Experiment
Even if everything is wired correctly, nothing will happen at first. But only if you are familiar with the rel-
evant safety guidelines on working with devices that are to be connected to the mains as per VDE and know
how to observe them, should you interconnect the circuit with an external circuit
When you then touch the individual points at the input that have the audio signals of the circuits to be
tested, you will see the needle of the moving-coil meter moving – no matter if the amplitude is just a few
mill volts or several volts. This tool comes handy, if you need to quickly locate a broken level in an audio
circuit.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.146.
172
Components required:
2 x 2N3904 transistors,
1 x BAT85 Schottky
diode, 1 x 2.2 kΩ resis-
tor, 1 x 4.7 kΩ resistor,
1 x 10 kΩ resistor,
1 x 220 kΩ resistor,
1 x 1 MΩ resistor,
1 x 1 μF electrolytic
capacitor, 2 x 10 μF
electrolytic capacitors,
1 x 100 μF electrolytic
capacitor, 1 x moving-
coil instrument,
1 x breadboard, 1 x 9V
battery with clip con-
nector
Fig. 2.146: Simple signal
tracker with Piezo element
Advertisement
Table of Contents
