monostable 555

The circuit is a 555 timer configured as a monostable multivibrator. This circuit can be found in multitude of references such as books, magazines, technical manuals, web pages, etc. but I created this circuit because I have to cite this in some other circuits that I created. Notes: The duty cycle for the trigger clock/pulse is set to 62.5 % instead of the more familiar 75% so that the graph will be displayed quickly after 125 µs instead of 150 µs simulation time if in Simulation settings, Initial conditions is set to User defined. The input signal, which provides a repetitive active LOW trigger pulses, commences at high (inactive) state but the output is also initially set high. This is the same behavior even if the Rise time (TR) of the Clock Voltage source is set to 0 s. The output switches low as the timing capacitor voltage makes its first crossing of the control voltage. This results to having a leading pulse that is unevenly spaced from the others. Subsequent cycles appear to work properly.