The Att-Vert is an attenuverter Tile with a fixed voltage reference normaled to the input. An attenuverter allows you to scale and/or invert the polarity of the input signal. When the control knob is in the full counterclockwise position the output will be the same magnitude as the input but phase shifted by 180 degrees (inverted). As the knob is rotated clockwise the amplitude of the signal is attenuated and becomes zero at the center position. Once past the center position the output is in phase (non-inverted) and attenuated until reaching the full clockwise position where the output will be the same as the input. The input jack is normaled to 5V so when the input is not patched the Att-Vert acts as an adjustable voltage source where the output is -5V in the counterclockwise position and +5V in the clockwise position. A bi-color LED indicates the polarity of the output by color and the amplitude by intensity. The indicator LED is red for voltages greater than zero and green for voltages less than zero.