I am measuring the voltage at the pins of a plug after disconnection from mains supply. The requirement being that the voltage "x" seconds after disconnection should be less than a certain value. Another requirement being that the measurement should be made when the disconnection from the supply happens as close as possible to the peak value (positive cyle or negative cycle). This second requirement is what i am having trouble with.
So for a 110Vac, the disconnection should happen either at + or - 155V (110 sqrt (2)) with a tolerance of 5v. To do this we have a set up where a separate 9v supply is turned on or off along with the mains supply. So when the 9V signal is on, the ac mains is on, when 9v goes off, the ac mains is shut off from the plug pins.
We connect the plug pins voltage probe to CH1 and the 9V signal to CH2. Then we set the trigger to CH2, falling edge, 9V. So the next time the switch is off, it gets triggered. BUT there is nothing to make sure the trigger happens at the peak of CH1 mains voltage. We have to do multiple switch on and off to get the trigger to happen exactly at the peak of the CH1.
Is there a way to make sure the trigger happens at the peak of the mains voltage (positve or negative)?
Oscilloscope used is DPO2014B.
