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Minute Timer with alarm by IC555

This circuit uses a 555 IC timer number.This small, compact and portable. For the snooze alarm when some 10 or 15 minutes.It makes clear the brain is ready to continue to work.
When the switch S1 to enter a power supply circuit, it will be ready to go.The circuit includes a circuit IC1 Mono Stable for the delay.The switches S3-S6 as election time.If selected by S3, 5 minute timer.S4 is located at 10 minutes.S5 timer for 15 minutes and S6 is scheduled for 30 minutes.If you want to set for 10 minutes, switch S4 is followed by a switch S2 to start all the time.Work is that when switch S4 will allow the current flowing through R4 will flow through the switch S4 to C2.Acting with a delay charge and discharge completely.Then send a signal to Pin 7 and 6 of IC1 resulted BZ1 beeps Buzzer out.
The time value is determined by the value R2, R3, R4, R5 and C2.If you want to set up a long time, it increases the R and C, but would spend less if it reduced the R and C.

Be the first to comment - What do you think? Posted by admin - October 21, 2010 at 7:45 am

Categories: Timer Tags: IC 555 timer, timer alarm

Time Delay Relay by 555

A time delay relay is a relay that stays on for a certain amount of time once activated. This time delay relay is made up of a simple adjustable timer circuit which controls the actual relay. The time is adjustable from 0 to about 20 seconds with the parts specified. The current capacity of the circuit is only limited by what kind of relay you decide to use.

Read More Soure:http://www.aaroncake.net/circuits/relaytim.asp

Be the first to comment - What do you think? Posted by admin - June 11, 2008 at 11:08 pm

Categories: Timer Tags: IC 555 timer, Time Delay, Timer Switches

PBS Switch Debouncing by 555

This circuit will remove the transient spikes and contact bounces from a non-latching push button switch.

Using a 555 timer as a monostable circuit, it is easy to build a good switch debouncer circuit. There are many circuits for SPDT debouncing, but not many for a normally open, push-to-make press button switch (PBS). The 555 monostable gives an output pulse of around 20 msec with component values shown. The formula for determining the output pulse is:

tout = 1.1 R1 C1