UM0922
Oscilloscope waveforms
Doc ID 17259 Rev 1
11/23
7 Oscilloscope
waveforms
The following waveforms were taken while testing the demonstration board with a 300 W
universal motor and no load applied. The purpose of these waveforms is to show how MCU
signals are managed and synchronized to the voltage mains. These signals are valid and
remain unchanged for any universal motor connected to the demonstration board. The only
signal to change is the output current, which depends on the selected working level and
motor size.
Figure 5.
Motor running at the lowest power level
The gate pulse (blue) is applied to the Triac with a firing angle of 8.5 ms with respect to the
voltage mains (brown). Once the pulse is applied, the Triac turns on and begins delivering
power to the motor. The purple waveform shows the current flowing through the motor. The
demonstration board is now working at level 1, delivering the minimum power to the motor.
