1.1. How to determine the polarity of the old style piezo?

The polarity of the PZT can be determined as follows:

1. Connect both poles of the connector of the PZT to an oscilloscope (time base approx. 50ms/div, y-axis 200mV/div).
2. Slightly tap the head of the PZT with your finger. As a result you should get a voltage pulse on the oscilloscope. 

• Positive Amplitude  -> + pole of the piezo is connected to the inner conductor of the oscilloscope BNC connector .
• Negative Amplitude -> + pole of the piezo is connected to the outer conductor of the oscilloscope BNC connector .