how about this ramp generator which i found in youtube?will this work with scr instead of the transistor?coz i think(correct if i am wrong) it has more "negative resistance" about which he is talking!

http://www.youtube.com/watch?v=rpGOKGrcpAk

 

what does "micro" mean?

In this context it means microprocessor, or microcontroller or micro-control-unit.