STM Electrode Test

The electrode test tells you if you electronic components are working correctly. The principle is that by stimulating the inner electrode of a piezo with a square wave signal from the oscilloscope, you can see a square-like charge/discharge response (~2V) on the outer electrodes of the same piezo.

• Because all of the outer piezos have their inner electrodes connected, you can stimulate their common input ABCZ and check the response of each outer piezo's outer electrodes (AX-, AX+, AY-, AY+; BX-, BX+, BY-, BY+; CX-, CX+, CY-, CY+). 
• Similarly, you can stimulate the inner piezo's inner electrode Z, and measure the inner piezo's outer electrodes. These outer electrodes are daisy chained together inside the STM, and so you can measure the X-X+Y-Y+ BNC plug.
• If you stimulate the inner piezo's inner electrode (Z) and measure the outer pizeos' outer electrodes (AX-, AX+, AY-, AY+; BX-, BX+, BY-, BY+; CX-, CX+, CY-, CY+), you should see no response (in reality a smaller response of ~300mV).
• Conversly, you should see the same response (or lack thereof) if you stimulate the outer piezos' inner electrode (ABCZ) and measure the inner piezo's outer electrodes (X-X+Y-Y+).
• (Optional) If you stimulate an outer electrode and measure the other outer electrodes on the same piezo, you'll see a square-ish charge/discharge response that's smaller than if I stimulate the piezo's inner electrode.