thanks peterb!!!but I am looking for a cheaper alternative to oscilloscope (w/ trigger).
This circuit must detect a voltage spike greater than ...say 26volts and if it detects one, there should be a way of knowing it like a simple LED.
I tried to use a comparator but op-amps operate at not more than 10MHz response and what I know is that , spike ranges at 10-100 nanoseconds that is why we need high bandwidth scopes w/ trigger to detect one.