Please help me with the attached pic.
All what I as trying was to understand SCR control.
It consists of a full wave bridge rectifier(Input 230V AC) whose output is fed to a series combination of a 2Mohm resistance(by having 2 ,1M Ohm resistance in series) + 1 LED connected to anode of SCR(BT151) and then cathode of SCR connected to other end of output of rectifier.I decided to trigger the gate(though foolish when working with a frequency of 50Hz but still) to the joint of 1M and 1M expecting that the LED will glow.But after giving 2-3 pulses there was a big flash and the SCR broke open.Why did it happen this way?I have attached datasheet as well as circuit diagram.
Futher,I was about to implement SCR phase angle control using Atmega 32 by following aplication note AVR 182 and AVR422.
What I havent got yet is,how is the SCR is triggered.The datasheet says Igt=5ma and Vgt=0.6V but these are for VD of 12 V.How do these translate when working with 230V.