The police suspects that the terror group, possibly Indian Mujahideen, has acquired new levels of sophistication. “Indian Mujahideen had used microprocessor timers in the blasts at Surat and Bengaluru, mechanical alarm clocks in the Hyderabad twin blasts and cellphones alarms in certain other blasts. Using digital timers with silicon controlled rectifiers (SCR) in the bomb circuits need additional skills,” said a state police official.
“The bombs weigh three to five kg and the explosive slurry is stuffed in metallic containers. Based on the impact crater at the explosive site, the splinters spread over 200 feet. The impact was taken by a car for one of the bombs as it might have been dropped at the foot rest,” said an official. “Even if there is a problem with the battery voltage, the SCR rectifies and passes the appropriate current. We are suspecting it to be a digital timer with SCR but some teams from other agencies disagree,” he added.
An SCR can be “fired” open and “shut” in increments far smaller than 1/60th of a second. It is a four-layer semiconductor device that doesn’t allow current to flow until it is triggered. Once triggered, it will only allow the flow of current in one direction. Meanwhile, sources said that Indian Mujahideen operative, Danish Riyaz, has revealed that they had resorted to robbery at Indore to pay for the advocates defending the accused in the Gujarat serial blasts. Deccan Chronicle