A selective timer circuit using IC 4060 and IC 555 is given here.As we all know that the IC NE555 was a timer and oscillator but the IC1 CD4060 was a 14 stage binary counter with a built in oscillator.The output of the IC1 will become high one after other and only one at a time so here we employ that IC as an source for the selective timing to be used.The last five outputs of this IC was used here.Lets move into the working of this circuit.The switch S2 should be a single pole five throw rotary switch.
WORKING:
The IC2 NE555 was wired as a monostable multivibrator and it was triggered by the high pulses from the IC1.Since the IC2 was wired as a monostable multivibrator the buzzer will produce the sound when the output goes high in it.The duration of the buzzer alarm was given by means of two components C3 and R5.The trigger pin of the IC2 will normally positive when the Q1 was forward biased by the high pulse the trigger voltage decreases due to the charging of the capacitor.When the capacitor was fully charged the pin 2 again becomes positive thus resulting in turning off of the buzzer.
The above given diagram was the pin diagram of the iC CD4060 and it illustrates the operation of this IC.Each pins will generate high pulses of certain frequency but the pin 3 will be generating the signal with high frequency.The frequency reduces to half as it moves from 3 to other pins.The frequency reduces to half as it proceeds from one pin to other pins.A variable resistor of 1.5M connected to the pin 10 and a capacitor of 0.22uF connected to the pin 9.The 12th pin of the IC1 was reset which enable to reset the timing cycle.The switch S2 was used in order to select the timer for the alarm.
See more circuits of NE555
WORKING:
The IC2 NE555 was wired as a monostable multivibrator and it was triggered by the high pulses from the IC1.Since the IC2 was wired as a monostable multivibrator the buzzer will produce the sound when the output goes high in it.The duration of the buzzer alarm was given by means of two components C3 and R5.The trigger pin of the IC2 will normally positive when the Q1 was forward biased by the high pulse the trigger voltage decreases due to the charging of the capacitor.When the capacitor was fully charged the pin 2 again becomes positive thus resulting in turning off of the buzzer.
The above given diagram was the pin diagram of the iC CD4060 and it illustrates the operation of this IC.Each pins will generate high pulses of certain frequency but the pin 3 will be generating the signal with high frequency.The frequency reduces to half as it moves from 3 to other pins.The frequency reduces to half as it proceeds from one pin to other pins.A variable resistor of 1.5M connected to the pin 10 and a capacitor of 0.22uF connected to the pin 9.The 12th pin of the IC1 was reset which enable to reset the timing cycle.The switch S2 was used in order to select the timer for the alarm.
See more circuits of NE555
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