2. Methods using an oscilloscope

2.1 Method using a dual-trace oscilloscope

The two voltages to be compared e ₁ (t ) and e ₂ (t ) are applied to the two inputs of the device. Using the gain adjustment knobs for each channel, and the framing knobs, we seek to superimpose the two average values (figure 11 ). If the phase difference is zero, the signals e ₁ (t ) and e ₂ (t ) merge on the screen; if there is a shift θ of the traces, the phase difference is given by : $\phi (°)=\frac{\theta }{T}360$