Monostable module

Description: In the monostable mode, the 555 works as a "one-shot" pulse generator.  Other applications of monostable mode include timers, pulse-width modulation (PWM), missing pulse detection,  touch switches, frequency divider, capacitance measurement, bouncefree switches  and so on. 

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• An example of monostable mode

The following schematic has been taken from buildcircuit.com. The following circuit can be used for making a touch switch, light operated switch, clap switch, dark sensor, etc. EXPERIMENT 1: DARK SENSOR USING LDR AND 555 Use VR1(variable resistor)  for adjusting sensitivity of the dark sensor. You can use fixed resistor in place of the variable resistor. WATCH THE VIDEO:  EXPERIMENT 2: DARK SENSOR USING PHOTODIODE AND 555 Just replace LDR with a photodiode, connect cathode to PIN 8 and anode to pin 2 of 555, it simply works for the photodiode also. EXPERIMENT 3: TOUCH SWITCH A minor modification in the circuit makes it work as a touch switch. CLICK HERE FOR TOUCH SWITCH EXPERIMENT 4: MAKE A CLAP SWITCH