This circuit is configured in quad monostable mode of operation, which are four independent basic time delay circuits, each using a 555 type of timer. The single chip quad timer offer excellent timing and temperature tracking between the 4 separate timers. The monostable circuit is also sometimes referred to as a one-shot circuit, as it generates one fixed delay pulse every time it is triggered. In the initial state, the circuit is in the standby mode. The trigger input is at a high level, and the output is at a low voltage level. The discharge output at pin2 (pins 4,6,and 8 for the other 3 timers respectively) is on, and that clamps the capacitor C to ground potential. When a negative going trigger pulse is delivered to input at pin3 (pins5, 7 and 9 respectively), the flip-flop inside the 555 timer is set to turn off the transistor at pin2 and the RC network starts charging towards V+, with a time constant equal to R x C. Capacitor C is charged towards 2/3 V+ and when its voltage reaches that threshold